User talk:KSmrq

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Contents 1 Utility 2 Greeted 3 Wallpaper group & Crystallographic restriction theorem 4 "mirror" vs "reflection axis", and other things 5 superscript template 6 mathbot links 7 Manifold 8 "German pride" apology 9 Graphics 10 XML-safe WP for MathML 11 Mathematics and God 12 hyperlinks in equations 13 Binomial coefficient 14 Please vote 15 Boolean algebra 15.1 peace 16 Graphviz 17 Gosper 18 Boolean algebra intro 19 0.999... and all that 20 MathML Characters 21 Kudos 22 Please comment on the current Math Collaboration of the Week 23 Pythagorean theorem 24 Infinitely nested commutators 25 your opinion sought 25.1 Part 2 25.2 Part 3, color palette 25.3 Part 4 25.4 Part 5 25.5 Part 6 25.6 Part 7 25.7 Part 8 26 Edit to manifold 27 Function, math writing style 28 Proof_that_0.999..._equals_1 29 Fixed-point 30 Common sense 31 Weather and chaos 32 here's your barnstar 33 WP:RD/Math#caculate_displacement 34 Psychic 35 Changes to the signature program article 36 Help desk 37 Surface Normal Outward Normal Left and Right hand rules 38 Admin? 39 Your reverts to Proof that 0.999... equals 1 40 Talk:Bernard Haisch 41 Blanking responses on Mathematics ref. desk 42 Preview your edits at "order (group theory)" 43 WP:RD/M 44 Congratulations! 45 You're famous 45.1 Quote 46 Wikifascist 47 Loved your Greetings 48 Reversion 49 A polite request for KSmrq 50 re Your Message 51 Reversion of the day 52 ISBNs 53 A London Life 54 4RR 55 Do you want to add your advice to the Math Manual of Style? 56 0.999... 57 Please archive your talk page! 58 Slerp Formula 59 Richard Gabriel / ISBN 60 Floating point and e 61 Image:Villarceau_circles.gif 62 CH 63 Mets501 64 Euclidean space edit 65 RefDeskBot 66 Irrelevant ramblings? 67 =^def 68 Please behave 69 Etiquette 70 Etiquette Revisited 71 Differentials 72 Mathematics and God 73 ISBN 13s 74 Snare technique 75 Thanks for Helping ... and sorry for mistaking someone else for your efforts 76 Fixing redirects; and also archiving 77 Sorry ! 78 Computer algebra systems 79 Continuity and Givens rotations 80 Koch's snowflake 81 Help with rotation matrix 82 Ed Pegg, Jr. 83 One or more 84 Happy Pi Day!! 85 Graph 86 Plücker (and Grassmann) coordinates 87 the alhambra

[edit] Utility

• Edit stats

• The Wikipedia Creed
• Hillman critique
• Ikkyu2 critique

[edit] Greeted

Welcome!

Hello, and welcome to Wikipedia. Thank you for your contributions. I hope you like the place and decide to stay. Here are a few good links for newcomers:

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I hope you enjoy editing here and being a Wikipedian! By the way, you can sign your name on Talk and vote pages using three tildes, like this: ~~~. Four tildes (~~~~) produces your name and the current date. If you have any questions, see the help pages, add a question to the village pump or ask me on my Talk page. Again, welcome! - UtherSRG 16:21, Jun 4, 2005 (UTC)

[edit] Wallpaper group & Crystallographic restriction theorem

Greetings KSmrq and welcome. I noticed you added an external link for the crystallographic restriction theorem on the wallpaper groups page. Just letting you know I intend to write a more complete article on that topic in the next month or two. That external link is a little misleading, the content there suggests the result is identical in the higher dimensional cases, which is not true (e.g. there are 5-fold rotations in 4-space etc). Feel free to beat me to it if you like. Dmharvey Talk 14:58, 5 Jun 2005 (UTC)

Hello again. Before I respond to your comment, I wanted to mention that the convention on WP appears to be to reply to comments in the location that they were posted (with indent), even if that's your own talk page. It makes it easier to follow the thread of conversation; you can use your watchlist to keep up with things. Please correct me if you think that's not true. (I'm fairly new around here too.) Actually, I'll paste your comments here and pretend that nothing happened :-) Dmharvey Talk 21:58, 5 Jun 2005 (UTC)

Re: Wallpaper group

Agreed, the geometric proof for 2D cannot be used unchanged for all dimensions. However, the linked page seems adequate for wallpaper groups, and it is explicit about its limits:

We will give the proof for ℝ². The proof for ℝ³ is similar. It is harder for higher dimensions!

One generic proof depends on the transformation matrix having only integer entries in terms of a lattice basis. But one of the nice properties of your edits is the introduction of a great deal of visual material, and the 2D geometric proof, though more limited, seems more in line with that style.

Two dimensions of tension are apparent in content of this nature: abstract mathematics versus concrete examples, and specific (2D only) versus general (such as 3D crystallographic groups). Given the topic of the entry, it seems wise to stick with specific and not worry about higher dimensions. As for mathematics, readers may be young or inexperienced, and we'd hate to give them a bad taste, to make them feel like this material is unpleasant or too difficult. A matrix proof might do that.

KSmrq 21:25, 5 Jun 2005 (UTC)

I fully agree. I intend the following to happen. The wallpaper group page needs lots of pretty pictures and an informal explanation (which just got another rewrite today), because it is one of the very few mathematical topics that is accessible to just about anybody. On the other hand, it needs some formal definitions, along the lines of what I have included, to satisfy mathematicians. (And it still needs a lot of work on that count, e.g. there is only the barest mention of lattices.) The only mention of higher dimensional cases should be: (1) very briefly in the introduction, (2) slightly more detail (but still no more than a sentence or so) in the formal section. The article on the crystallographic restriction theorem should include (1) the easier geometric proof that works in 2-d and 3-d, and also (2) the high-tech proof for higher dimensions. I am a very big fan of the idea that WP should make mathematics completely accessible to anybody who has the barest minimum of background necessary to understand a given topic, yet should also give as much rigour, detail and comprehensiveness as would satisfy the most demanding mathematician. Dmharvey Talk 21:58, 5 Jun 2005 (UTC)

[edit] "mirror" vs "reflection axis", and other things

Hi KSmrq,

First, just want to say thanks for your work on Wallpaper groups and Euclidean plane isometry. It's nice not to be the only person working on something. When I look around on the web for other articles on this topic, I think it is possible for the wikipedia article to become the definitive resource. But it will take a lot of work and time. (Just found out yesterday that we'll need to wait about 40 years or so for Escher's work to become copyright-free... oh well....)

Ain't it grand? So many times with technical writing we work in solitary confinement; not here. And speaking of copyrights, there was a comment that many of the wallpaper images came from the Grammar of Ornament; is there a potential problem?

The author of Grammar of Ornament died in 1874, so the copyright has well and truly expired in all jurisdictions. Dmharvey Talk 28 June 2005 10:48 (UTC)

To business: want to discuss some terminology on these pages. I've noticed you've used the term "mirror" quite often. There's a little ambiguity here. Sometimes you use "mirror" to mean the isometry itself, and sometimes you use it to refer to the axis of reflection. I think it might be better to stick to one meaning, or at least make it clear somewhere that it can be both. Perhaps the term "mirror" should be introduced right near the beginning, where "reflection" is defined. Also, sometimes it seems that "mirror" includes glide reflections, and sometimes it doesn't. I've tried to distinguish my use of "reflection" and "reflection axis" rather carefully.

The reason I am a bit hesitant is that it has been many years since I've seen a book on this topic, and I'm not sure whether "mirror" is used at all in the literature (including stuff aimed at non-specialists), or whether you are simply using it to make the material more palatable.

What's your take on this?

I hadn't noticed a conflict between meanings of mirror. I'll check and try to clarify where necessary. In the orbifold notes at the Geometry Center the term mirror is used often, with emphasis on the idea of a "mirror string", for example. A mirror as transformation unambiguously selects a line of fixed points, which in the physical world would be the (one-sided) mirror itself. If we want to refer to the line only, we may call it a mirror line. Likewise, the mirror line uniquely determines the mirror transformation.

---

OK, I've reviewed my contributions on wallpaper groups and Euclidean plane isometry. My use of the term mirror seems to be consistent, as I read it. The meaning is always a geometric line implying a reflection isometry. By itself, a mirror (line) cannot imply a glide reflection, only a reflection. In a symmetry group, a mirror line parallel to a translation inevitably generates a glide as well; however, we call it a mirror line if we have mirror symmetry without translation. We only label a line a glide axis if it does not allow reflection without translation. Still, if you find a particular sentence or paragraph that particularly troubles you, point it out. However, we should probably put such discussions on the talk page for the article in question, since later editors are unlikely to find their way to my talk page.

BTW do you have a reference for where Conway introduced orbifold notation? Thanks for writing that section, it's great.

To be more precise, Conway's notation applies to 2-orbifolds. As you probably know, a great deal of interesting and useful mathematics circulates informally long before it achieves publication. Mathworld cites Zwillinger, CRC Standard Mathematical Tables and Formulae, 1995. Goodman-Strauss refers to a talk documented in 1993, but given often before that. And these Oak Ridge Crystallographic Topology pages give the earliest specific citation I've found in a brief web search:

• J. H. Conway, "The Orbifold Notation for Surface Groups", in Groups, Combinatorics & Geometry, M. Liebeck and J. Saxl, Eds., Cambridge University Press, pp. 438-447 (1992).

Yes, I found that reference and pulled it out of the library. Conway states in it that this is the first place the notation is used; I find no reason not to believe him. The book is a record of the proceedings of the L.M.S. Durham Symposium on Groups and Combinatorics, July 5-15, 1990. Dmharvey Talk 28 June 2005 10:58 (UTC)

Finally, is the term "rosette group" the correct name for what I called the "two-dimensional crystallographic point group" (under Wallpaper group#The independent translations condition)?

Close, but I think not. A crystallographic point group includes the restriction of lattice compatibility; a rosette group is only required to be discrete (and hence finite). Thus D₈ would be rosette, but not crystallographic. Consider what the chemists might say if we were talking about a single molecule in 3D; the molecule has point symmetries with no lattice restrictions. Because you specifically said "crystallographic point group", we have a distinction.

In speaking of ornaments, the 2D pattern groups seem to be called wallpaper, frieze, and rosette, names that make sense in that context. Frieze may also be replaced by strip or border. Rosette groups get far less mention, at least by that name; but I hesitate to say point group precisely because of the crystallographic confusion. Hubcaps (aka wheel covers) are a popular teaching tool. KSmrq 2005 June 28 09:42 (UTC)

Thanks, that's very interesting. You seem to know a lot about this stuff. I just pulled out a few books, maybe I'll look over them the next while so I can write with a little more authority! :-) Dmharvey Talk 28 June 2005 10:58 (UTC)

I've enjoyed playing with the mirror ideas previously, though more in a 3D setting. A friend runs a rock shop and an amateur rockhound group, and I wanted to make the mathematics more accessible. The mirror approach is the simplest I've found in the literature I've examined. So much of what we learn today is based on coordinates and formulae that the pure geometry is lost.

I'm tinkering (in SVG) with an illustration of translation addition, along with other isometry images; it's pretty to see what can be shown without equations.

And I think it's good to stimulate that part of the brain. Apparently Hilbert and Cohn-Vossen thought so! Conway, Doyle, Gilman, and Thurston liked the idea enough to use the same title for a summer workshop and a Princeton course, "Geometry and the Imagination". That's pretty good company. KSmrq 2005 June 28 12:26 (UTC)

Dmharvey Talk 11:57, 26 Jun 2005 (UTC)

[edit] superscript template

That superscript template you're using doesn't look very good on my browser (either Safari or Mozilla (mac)). The superscripted character is quite a long way from the base character. But honestly I've had enough of this discussion. :-) Dmharvey Talk 6 July 2005 19:47 (UTC)

[edit] mathbot links

Please note that it was not my bot which made the link to finite in crystallographic restriction theorem. But I agree that the links to positive number and negative number being a bit silly. I will not link to those anymore.

Did you find useful any of the other links my bot made? You can reply here to keep the conversation in one place. Oleg Alexandrov 15:47, 18 July 2005 (UTC)

Marginally. I was too annoyed to rip them all out, as I had already made a number of substantial edits before I noticed the bot additions. I spend hours writing and illustrating, and thinking carefully about what to say and what to omit. This is Wikipedia, where anyone can edit, but I'd strongly prefer a comparable amount of care go into modifying an article. The bot additions are clumsy and heavyhanded. With wise human oversight, suggestions of links could be helpful; but, for example, I had included links for rotation and for symmetry in the opening sentence, yet the bot added a link in the second paragraph for the phrase rotational symmetry. The link for determinant is reasonable. But we must consider the reader. The higher dimension generalization is aimed at a more sophisticated reader, who surely does not need a link for integer! Wikipedia guidelines caution about overlinking, which the bot blatantly ignores. I don't appreciate cleaning up after it. But I do appreciate you asking and trying to be helpful. Thanks. KSmrq 06:45, 2005 July 19 (UTC)

Good points. You made me realize that the linking operation can't be done with a bot, and that is very much appreciated. For future reference however, if you don't agree with something, a message on the talk page (say my talk page) would be much more helpful than an (annoyed) edit summary. This because it was rather an accident that I saw your comment; one can't possibly have on the watchlist all the pages a bot can operate on, and besides, information in the edit summary gets obscured as soon as there is a more recent edit summary.

I saw you removed some of the links while kept the other. I assume you used your judgment of what is helpful and what is not, so I will not attempt to remove the ones you left. Cheers, Oleg Alexandrov 11:47, 19 July 2005 (UTC)

[edit] Manifold

As I wrote on Talk:Manifold/rewrite, I think it is best if we let it rest for a week and calm down a bit. It would take me quite some time to react on the points you and Markus raise with the required care and I am afraid the situation would get out of hand before, so please take a rest and work on something else. See you in a week, Jitse Niesen (talk) 22:34, 26 July 2005 (UTC)

I appreciate your concern. I was trying to post a detailed response to Markus and noted at the end that I had used a great deal of emphasis. :-)

You'll likely have noticed I did take a break earlier. You cannot know I composed a message for your talk page before I added my comments to Markus on Talk:Manifold/rewrite. However, I did not feel right involving you, and decided I should address Markus directly. Since you have no prior history with me, I should inform you that I've been on the internet for decades, and seen flame wars. I do my best to turn the talk more productive, to improve the "signal to noise ratio", as it were. It is my intention to do that with Markus as well, though we do seem to have a communication barrier.

That said, I'm not convinced you have chosen the best route forward. I don't like to let misunderstandings fester, which is what I fear will happen. I suspect, from various hints, that Markus has been upset ever since my first edit. Thus he pauses briefly then reverts, not literally, but in the sense that the forward progress is discarded. I have tried hard not to do that, but rather to incorporate stated (and unstated) concerns in each new draft. For naught.

Thus I decided to confront the issue head-on, fully aware that some flames might fly. I don't want the flames, I don't like them, and I don't think they are helpful. But neither is it helpful to pretend strong emotions don't exist when they are clearly affecting behavior. I see a page that is nearly stalled, and I see Markus' behavior as the main factor. It is hard to confront someone, and almost impossible to do it without unintended side effects. I suppose I'm willing to do it because of the "never again" idea associated with the Holocaust; if we don't speak up early we'll have much worse to deal with later. Much as I hate confronting Markus myself (and I really do hate it), I cannot in good conscience ask someone else to do it for me. So I killed the message I was composing for your talk page, knowing what I had to do.

Frankly, if it were only a matter of the manifold article, so what; one weak piece of writing on all of Wikipedia is a drop in the ocean. For that matter, Wikipedia itself is only one drop in the larger web. But I've seen it too many times; I know where the road leads. If the behavior is allowed to repeat without correction, it grows stronger and more destructive. I saw repeated expressions of discomfort from others, yet no one willing to step forward; that's quite common. I do it because I'd rather confront Markus now so I don't have to deal with worse later. But if you want to take it on yourself, please do so. I'm more than happy to let someone else do the confronting, so long as it does get done. The main difficulty is that I don't know that someone else can represent my concerns. To that end, here are excerpts from the response I was trying to post for Markus when you froze the page:

• You ask "… what good is it to feature an incorrect article?" Sigh. Do you really expect that every article on Wikipedia is 100% correct? Even the ones you have worked on? From time to time I have read featured articles and made corrections. Are those articles worthless? Again I insist, you are missing the bigger picture. It is quite possible to write an article that satisfies your sense of correctness, yet which is unreadable. What is the good of that? I use a simile, which means I say "is like", using colloquial English in an introduction, and you can't live with it. That's an absurd demand for "correctness"!

• I am more familiar than you with what manifold means in English. It does not mean repetition, and I never claim so. Nor do I claim that Riemann uses Mannigfaltigkeit to mean repetition. The words are not false friends, as you claim; but that's beside the point. I'm not giving a definition; I'm not giving a translation. I'm giving a mnemonic, a way to help people associate the idea with the word. Somehow that eludes you. We can go over Riemann paragraph by paragraph, line by line, and for no gain. I can see what he's getting at; you cannot seem to see what I'm getting at.

• My frustration is evident in the number of times I've used various forms of emphasis. Let me just close with this thought: Really great mathematics is drawn from insight, not pedantry. Consider Bishop Berkeley's critique of Newton's fluxions, and ask yourself if that means Newton was a poor mathematician. We may publish to different standards today, but we can only hope to think with Newton's insight. Berkeley is a footnote, Newton the main text. If I had to choose, I'd rather inspire a Newton than a Berkeley. Fortunately, this is a false dichotomy; we can have both, if you will only let both live.

Well, that's more than enough for now. I promised to fill in another section of Wallpaper group. Thanks for stopping by, and good luck. KSmrq 00:31, 2005 July 27 (UTC)

[edit] "German pride" apology

Greetings. On the manifold/rewrite talk page I made a remark referring to German pride. It has been brought to my attention that such a remark could be offensive in the context of German culture. Please let me assure you I intended no offense, and sincerely apologize if my attempt to be friendly may have backfired. I will apologize on the page itself when it is unfrozen, but I am mortified at my blunder and did not want to wait until then to speak to you personally about this one specific issue. KSmrq 22:10, 2005 July 30 (UTC)

Thank you for your apology. In fact I felt a little bit offended and didn't realised it was an attempt to be friendly. I really hope we can work something out satisfying both of us. Markus Schmaus 15:57, 31 July 2005 (UTC)

[edit] Graphics

How do you make your SVGs? With what program? Thanks, Markus Schmaus 12:06, 7 August 2005 (UTC)

The source SVG files I make with a text editor. I have tried Inkscape, but so far it falls short of my desires. My development loop is to edit the source, then render with Adobe's browser plugin. Once I am satisfied with the appearance, I use Batik to produce a PNG. Finally, I add text information to the PNG, possibly reduce the colors or alpha for compression, and place it on Commons.

For some illustrations I have used external calculations, as from a symbolic algebra program, to assist with numerical details. My content is primarily mathematical, not artistic, so this is feasible. Also, I have a great deal of experience with computer graphics, which makes it easier for me to work in this primitive way. In the past, I preferred to make illustrations with a commercial program called Canvas. However, I lack a modern version that can produce SVG output.

For the Web, I confine myself to W3C standards: SVG, PNG, JPG, XHTML, MathML, CSS. Beyond that, I look for cross-platform, cross-browser, and free or open-source solutions.

Example. To make the illustration of circle-slopes-as-manifold-chart, I relied on two familiar Pythagorean triples, (3,4,5) and (7,24,25), which yield simple and exact decimal coordinates (0.6,0.8) and (0.28,0.96). I distributed the values relatively evenly around the circle, leaving room for the interior triangles and their labels. I deliberately included antipodes 1/3 and −3, both to stimulate curiousity and to provide insight into the t = 1/s transition. The pair 3/4 and 4/3 subtly suggest reciprocals occupy mirror positions. I placed the labels at the point positions, then adjusted them for clearance. I chose a sans-serif font face that had the Unicode fractions I needed. I chose a font size that would be readable in the thumbnail. For the segment labels I used decimal fractions at a smaller size, both to distinguish them and to fit. The colors (red, green, yellow, blue) are sRGB values I calculated based on published research results on human vision. I chose line thickness, dot size, and color placement to harmonize with the previous illustration. The colors of the blue and green dots are hard to distinguish, as predicted by vision theory; but I felt that was less important in this illustration. I adjusted the dasharrays to get clean corners. I displaced the horizontal lines vertically up and down by half a line-width so they would not overlap. And so on.

In other words, the appearance of the figure has very little to do with a program, but a great deal to do with my attention to (obsession with?) detail, and with my choices based on experience in mathematics, graphics, and typography. I cannot in good conscience recommend this strategy to others; it is time-consuming, and requires an uncommon background. KSmrq 20:53, 2005 August 7 (UTC)

Thanks for your answer. I allmost suspected, that you do your SVGs with a text editor only. I did some research on the web and found a geometrical construction program which might be more appropriate for me.

By the way, it took me pretty long to grasp the above example. Maybe something like

<?xml version="1.0" encoding="utf-8"?>
<svg width="1014" height="592">
<ellipse cx="505.12020519966717" cy="296.47827308529054" rx="95.72940535020797" ry="95.72940535020797" style="stroke:rgb(0,0,0);fill:none;stroke-width:3"/>
<line x1="409.3907998494592" y1="296.4782730852906" x2="600.8496105498751" y2="105.0194623848746" style="stroke:rgb(180,0,0);stroke-width:1"/>
<line x1="600.8496105498751" y1="105.0194623848746" x2="594.0" y2="118.0" style="stroke:rgb(180,0,0);stroke-width:1"/>
<line x1="600.8496105498751" y1="105.0194623848746" x2="587.0" y2="112.0" style="stroke:rgb(180,0,0);stroke-width:1"/>
<line x1="409.3907998494592" y1="296.4782730852906" x2="600.8496105498751" y2="392.2076784354985" style="stroke:rgb(0,0,178);stroke-width:1"/>
<line x1="600.8496105498751" y1="392.2076784354985" x2="586.0" y2="390.0" style="stroke:rgb(0,0,178);stroke-width:1"/>
<line x1="600.8496105498751" y1="392.2076784354985" x2="590.0" y2="382.0" style="stroke:rgb(0,0,178);stroke-width:1"/>
<path d="M 406.0 293.0 H 411.0 V 298.0 H 406.0 Z" style="fill:rgb(0,124,0);stroke:rgb(0,124,0);stroke-width:1"/>
<line x1="601.0" y1="1309.0" x2="601.0" y2="-718.0" style="stroke:rgb(0,0,0);stroke-width:1"/>
<path d="M 598.0 102.0 H 603.0 V 107.0 H 598.0 Z" style="fill:rgb(180,0,0);stroke:rgb(180,0,0);stroke-width:1"/>
<text x="606.8496105498751" y="123.0194623848746" style="font-size:0;fill:rgb(180,0,0);font-weight:normal">1</text><path d="M 598.0 389.0 H 603.0 V 394.0 H 598.0 Z" style="fill:rgb(0,0,178);stroke:rgb(0,0,178);stroke-width:1"/>
<text x="606.8496105498751" y="410.2076784354985" style="font-size:0;fill:rgb(0,0,178);font-weight:normal">1/2</text><path d="M 502.0 198.0 H 507.0 V 203.0 H 502.0 Z" style="fill:rgb(180,0,0);stroke:rgb(180,0,0);stroke-width:1"/>
<path d="M 560.0 370.0 H 565.0 V 375.0 H 560.0 Z" style="fill:rgb(0,0,178);stroke:rgb(0,0,178);stroke-width:1"/>
</svg>

or

<?xml version="1.0" encoding="utf-8"?>
<svg width="1014" height="592">
<ellipse cx="570.0" cy="296.0" rx="3.0" ry="3.0" style="stroke:rgb(0,124,124);stroke-width:1;fill:none"/>
<ellipse cx="507.0" cy="296.0" rx="63.375" ry="63.375" style="stroke:rgb(0,0,0);fill:none;stroke-width:1"/>
<path d="M 478.0 235.0 H 483.0 V 240.0 H 478.0 Z" style="fill:rgb(0,0,0);stroke:rgb(0,0,0);stroke-width:1"/>
<line x1="507.0" y1="1309.0" x2="507.0" y2="-718.0" style="stroke:rgb(0,0,0);stroke-width:1"/>
<ellipse cx="507.0" cy="255.0" rx="3.0" ry="3.0" style="fill:rgb(180,0,0)"/>
<ellipse cx="507.0" cy="255.0" rx="3.0" ry="3.0" style="stroke:rgb(180,0,0);stroke-width:1;fill:none"/>
<ellipse cx="444.0" cy="296.0" rx="3.0" ry="3.0" style="stroke:rgb(0,124,124);stroke-width:1;fill:none"/>
<ellipse cx="507.0" cy="199.0" rx="3.0" ry="3.0" style="fill:rgb(0,0,178)"/>
<ellipse cx="507.0" cy="199.0" rx="3.0" ry="3.0" style="stroke:rgb(0,0,178);stroke-width:1;fill:none"/>
<line x1="443.625" y1="296.0" x2="481.41930190822734" y2="238.0170843253154" style="stroke:rgb(153,153,224);stroke-width:1"/>
<line x1="443.625" y1="296.0" x2="507.0" y2="198.7719234024745" style="stroke:rgb(0,0,178);stroke-width:1"/>
<line x1="507.0" y1="198.7719234024745" x2="503.0" y2="213.0" style="stroke:rgb(0,0,178);stroke-width:1"/>
<line x1="507.0" y1="198.7719234024745" x2="495.0" y2="208.0" style="stroke:rgb(0,0,178);stroke-width:1"/>
<line x1="570.375" y1="296.0" x2="481.41930190822734" y2="238.0170843253154" style="stroke:rgb(225,153,153);stroke-width:1"/>
<line x1="570.375" y1="296.0" x2="507.0" y2="254.69104104953345" style="stroke:rgb(180,0,0);stroke-width:1"/>
<line x1="507.0" y1="254.69104104953345" x2="521.0" y2="259.0" style="stroke:rgb(180,0,0);stroke-width:1"/>
<line x1="507.0" y1="254.69104104953345" x2="516.0" y2="266.0" style="stroke:rgb(180,0,0);stroke-width:1"/>
</svg>

might be easier to understand.

Sorry for cluttering your talk page. The SVGs don't use all the things you mentioned above, but just illustrate what I'm thinking about. Markus Schmaus 21:55, 7 August 2005 (UTC)

If we're going to talk about the specifics of this illustration much, we should move the conversation to the project. Briefly, yes, this mapping is equivalent to (scaled) stereographic projection, and that's simpler to illustrate. (The factor of 1/2 might be awkward.) But to do so would fight the point I make in the text, that charts need not be based on geometric projection. We don't want readers thinking of homeomorphisms or diffeomorphisms or manifold charts in general as embedded geometry; this example is (among other things) a small step in that direction. It's not such a bad thing if a little mental effort is required to understand the slope chart, because we soon introduce much more abstract examples where imagination is essential. I'm hoping high school students have already learned about the slope-intercept description of a line. (True in my time, but maybe no longer. Sigh.) Also, this particular circle parameterization is heavily used in applications; it is important in older algebraic geometry, and is one of the motivating examples for NURBS.

An alternative would be to drop the four-chart description and go straight to stereographic projection. KSmrq 23:51, 2005 August 7 (UTC)

[edit] XML-safe WP for MathML

Congrats on admin-ship. Dmharvey says you're the point man for the mathematics-writing community's efforts to have WP generate valid XML so that MathML can be enabled. It seems like a good idea for other reasons as well; I'd really like to see this happen. How's it going? Anything you could use help with? --KSmrq^T 23:36, 2005 August 27 (UTC)

Thank you for your interest, and for pointing out some documents on meta some time ago. The main problems at the moment are:

• As you know, Internet Explorer does not accept any of the XML media types, so we need to find a way to work around this. We might either have different media types depending on the browser (I don't know how much needs to be changed to achieve this) or embed MathML in a non-XML document (we need to evaluate the UniWakka trick, using different media types in the HTTP header and the HTML meta tag, and Jipsen's trick, using JavaScript to rewrite the HTML depending on the browser).
• I'm trying to get a test installation of MediaWiki running (currently at Berlios and Sourceforge), so that we can showcase the current state of affairs and test different approaches, but I haven't succeeded yet (it doesn't help that I'm now at my parents' place working via a modem).
• A lack of feedback from the developers of WP.

Any help on these points would be very welcome indeed. Do you have any experience with putting MathML on the web? By the way, what is your interest, MathML specifically, XML in general, or perhaps even more generally compliance with standards? -- Jitse Niesen (talk) 21:33, 28 August 2005 (UTC)

This page is interesting reading about MIME-type issues. Ian Hixie, a noted W3C expert, wrote about many of the issues some years ago. Note that Javascript/ECMAscript can break if the MIME-type changes. Perhaps IE7 will support "application/xhtml+xml"; that would be a Good Thing.

My interest is multifaceted. I have written a number of things using XHTML+MathML and CSS, all of which validate and look fine in Mozilla. I have had little interest in spending my personal energy compensating for Microsoft's misbehavior; for my own pages, use a standards-compliant browser or lose. WP and commercial web sites must cope.

What I really want is to be able to put mathematics on the web in a decent way, especially in a wiki. Currently MathML holds the most promise. MathML syntax is absurdly bloated, layout could use improvement in places, and fonts are awkward for a little longer; but otherwise it's great. I've both used and written mathematics typesetting systems, so have an appreciation of their strengths and weaknesses — and of the challenges they face — beyond that of most folks.

I'd be curious to talk to developers myself. Typically, folks work on things that specially interest them, that offer big rewards for little effort, or that someone insists be treated as a priority. Many programmers have grown up worshipping Microsoft; others feel it's a waste of timing fighting. Either way, if IE flouts W3C standards then developers may want to direct their efforts in more productive directions, especially if they themselves can be satisfied with subscripts and superscripts. One web-site author had this to say.

I prefer standards-compliance even when the standards aren't the greatest. That does not appear to be a strong force in MediaWiki development. Unfortunately, it's considerably harder to add it later.

We need to know who we're dealing with and what motivates them. And we need a champion; a developer who is strongly committed to making the Right Thing happen. It is so discouraging to "work around" Microsoft and to clean up old code that without a champion it probably won't happen. For my own life and career, I have found Everett M. Roger's ideas on diffusion of innovations a valuable guide. --KSmrq^T 00:59, 2005 August 29 (UTC)

[edit] Mathematics and God

KSmrq, can you please justify these edits you made to Mathematics and God? I'm particularly wondering why you removed the Hardy tidbit about rain.

FYI: the "minor edit" tag should generally only be used for purely prose edits, see Wikipedia:Minor edit. You also shouldn't delete content without explanation (unless its patent nonsense, etc).

SpuriousQ 02:46, 30 August 2005 (UTC)

[edit] hyperlinks in equations

Hi KSmrq, I read your comment about "scary" hyperlinks in equations on the village pump proposals page, I'd like to discuss this a bit further, but I thought it was getting a bit off topic for that post so I thought I should try here instead.

My question is, why do you think it's so scary? I happen to think it could be quite useful in certain situations.

Take something like . If this equation appeared in the article on modular arithmetic, then surely I agree with you, the surrounding article should be explaining very clearly what each symbol means. However, if it appeared in an article on quadratic reciprocity, we might prefer to simply make the symbol into a link to the modular arithmetic article, and not clutter things by again explaining the meaning of each symbol. Someone wanting to learn about quadratic reciprocity may well need some reminding about the meaning of the symbols. But if the equation appeared in an article on class field theory, we might well not make any link at all, since the intended audience should already know the meaning of the symbol. Symbols in equations can be "defined" or "undefined" depending on the intended audience, just like any word in any other article. Dmharvey Talk 23:58, 30 August 2005 (UTC)

Not that you asked me, but I find hyperlinks in equations ugly. I think the only place hiperlinks look good is in plain text, and even there when they are not in bold. Oleg Alexandrov 00:24, 31 August 2005 (UTC)

Hi there oleg, you seem to be implying that you've seen some hyperlinks in equations before. I don't think I've seen any before. Can you show me some so I can judge for myself? What if they were in the same colour, no bold, no underline -- almost invisible? Dmharvey Talk 00:59, 31 August 2005 (UTC)

Wherevere I saw them, I removed them, so I have no examples. :) Seriously, don't remmeber, been a while. That they can be almost invisible is what I also dislike. Ideally, I prefer

One has 5 ≡ 1 (mod 4), see modular arithmetic

to

One has 5 ≡ 1 (mod 4)

But that's just me. Oleg Alexandrov 01:09, 31 August 2005 (UTC)

yeah, I guess I see your point. I'll have to think about it a bit more. Dmharvey Talk 01:47, 31 August 2005 (UTC)

I see you guys have started the conversation without me. ;-)

Let's start with a simple example, "2+2=4". Most browsers will display the link in blue and underlined, so "+" looks like "±", which makes no sense. Or consider the dictum "For all primes p>2, p is odd." Now the underline changes ">" into "≥", and makes a true statement look false. Even without these disasters, links are a distraction we do not need in the middle of a formula. I hesitate to use footnotes on printed pages for the same reason (nevermind how horrible they are on the web or — gasp! — in the midst of a formula). If some of my readers might have to stop in the middle of a formula to look up a symbol, I probably haven't done my job well as a writer; I shouldn't put them in that position. For example, quadratic reciprocity depends critically on ideas of modular arithmetic, and I've got no business throwing equations at a reader before I've laid the foundation. In summary, a hyperlink in a formula is bad because:

1. it alters the notation,
2. it distracts the reader,
3. it indicates poor writing.

I don't use them, and if I see them I'll want to rewrite to eliminate them. --KSmrq^T 01:50, 2005 August 31 (UTC)

OK, I think I am starting to agree with both of you. However, I can't shake the feeling that there is no difference in principle between hyperlinking symbols in equations and hyperlinking words in a sentence. Assuming that we don't get the notational disasters alluded to above, what is the underlying difference? I can't seem to explain it to myself satisfactorily. Dmharvey Talk 02:20, 31 August 2005 (UTC)

I don't think there is an difference in principle. It is a matter of esthetics as far as I am concerened. Links embedded in formulas look ugly to me. Oleg Alexandrov 03:12, 31 August 2005 (UTC)

I can make a case that careful use of hyperlinks ameliorates all three complaints listed above. Rarely will underlining and blue coloring change the meaning of a word or phrase. For that to happen, color and underlining must have other meanings introduced. Distraction is a real possibility if links are used thoughtlessly and too often. However, writing that uses links in a definitional context where the reader is meant to look elsewhere if necessary can take care of both distraction and quality. Compare to the use of allusion, where used properly a reader has an enriched experience drawing on prior knowledge, but used improperly the meaning is lost. For example, if a Trojan horse attacks your computer it is acting through hidden treachery, as in Virgil's story of how the seige of Troy was won by the Greeks through their gift of the original Trojan Horse. And if you know the story, you'll understand the connection without following the links, just as you will understand "Beware of Greeks bearing gifts." (Spyware, anyone?) So in mathematical writing we should set out the context — especially required prior knowledge — before we focus exposition into a formula; links in a formula are always too late. The same is not true of text links. --KSmrq^T 06:09, 2005 August 31 (UTC)

[edit] Binomial coefficient

(I decided to move this to Talk:Binomial coefficient to see what others have to say. Oleg Alexandrov 00:46, 7 September 2005 (UTC))

[edit] Please vote

Hello. Please vote at Wikipedia:Featured list candidates/List of lists of mathematical topics. Michael Hardy 23:04, 14 October 2005 (UTC)

[edit] Boolean algebra

Ok, it's time for some of that gentle criticism you solicited on your main page...

Continuing to make changes to the intro, when Trovatore, Celestianpower, myself, and now Charles Matthews have asked you to stop, is not helpful. We have posted our objections to your version and support for Trovatore's version on the talk page and/or in history comments. Your Hasse diagram looks like it might be useful, but in the body of the article. Such complex material has no place in an intro, which should be written for a general audience. StuRat 13:19, 29 October 2005 (UTC)

Thanks for stopping by. My view of both facts and interpretation in these matters is so radically at odds with yours I see no point in discussing either. Nevertheless, I appreciate what appears to be a sincere effort at affirming our common humanity by speaking with me. Charles sought allies in what is apparently an on-going feud; now, too late, I see why. --KSmrq^T 16:17, 29 October 2005 (UTC)

I agree there is no pt in discussing our views any further. However, I do expect you to respect the consensus, especially when it consists of people on both sides of this issue. It now appears you are willing to do so, and I thank you for that. StuRat 16:22, 29 October 2005 (UTC)

I do not respect a consensus, because I do not think one exists. What I do respect is my time, which I do not wish to waste further on what appears to be a hopeless cause: jointly writing an opening that is both widely accessible and technically sound. --KSmrq^T 16:53, 29 October 2005 (UTC)

[edit] peace

Hi KSmrq,

I just want to say that I think you did a nice job on the intro. It's just not going to work in the current climate. It strikes me that this whole mess is partly a result of a linguistic accident; namely, that the standard term for the structure is the same as the name by which others call a discipline. If the structure were standardly called a "Boolean lattice" or "Boolean ring" I don't think we'd be having these difficulties.

The picture is very nice and I think it should be used. I do have one suggestion: Could the second row (with the doubletons) be reflected left-right? Then we could point out that every element is mirror-reflected from its complement, and describe meet and join in terms of the graph as well. --Trovatore 19:15, 29 October 2005 (UTC)

I also think the Hasse diagram should be used, just in the body of the article, not in the intro. And I think you are correct that it would not have been an issue had the article been under a more obscure name. While technically the intro to all articles should be accessible to the general public, if no member of the general public ever stumbles upon the article, then the issue never comes up. StuRat 19:21, 29 October 2005 (UTC)

A ray of hope! Accidental, but consider: All the discussion about what to name things might be handled by moving this article to Boolean lattice. The mathematicians will cope, and the engineers can hit a disambiguation page (or header) for Boolean algebra that makes them happy, too. Yes, articles usually live under their most common name; but if the alternative is the status quo …

That works for me, but convincing all the mathematicians to move it to Boolean lattice and make Boolean algebra into a disambiguation page may well be more difficult than the compromise we've worked out on the intro. If you want to make the suggestion on the talk page, I would be glad to lend it my support, however. StuRat 22:41, 29 October 2005 (UTC)

I have suggested many times moving the current Boolean algebra page to Boolean algebra (algebraic structure). I'm not as happy about moving it to Boolean lattice, because AFAIK virtually all the references in the literature refer to the structure as a Boolean algebra, so I think it's confusing to use a so-much-rarer name. --Trovatore 23:00, 29 October 2005 (UTC)

I prefer Boolean lattice, as Boolean algebra (algebraic structure) is still close enough that it may attract people looking for the content currently under Boolean logic, so would still need a general audience intro. StuRat 17:01, 30 October 2005 (UTC)

You're not going to type "Boolean algebra (algebraic structure)" by accident; you'll find it only by links, for example in whatever dab notice/page we put up. And you could find "Boolean lattice" the same way, since we certainly have to have an easy way for people to find the article after typing "Boolean algebra". So I don't think the claimed distinction holds. --Trovatore 17:51, 30 October 2005 (UTC)

Yes, but the folks looking for Boolean logic will get to the new disambiguation page at Boolean algebra, and won't be able to tell which they want from the names, so will end up in the wrong place by following the wrong link. If the name was Boolean lattice, then they would know that's not what they want. Under your suggestion, they might think "I was looking for Boolean algebra, and that article has it in the name, so that must be the one I want." StuRat 18:02, 30 October 2005 (UTC)

My proposal would actually be to move Boolean logic to Boolean algebra, and put a dab notice at the top for the algebraic structure. That's mainly because I also think "Boolean algebra" is the most common name for Boolean logic, and I can't think of anything good to put in parentheses for it. But hopefully it should take care of your concern as well. BTW we shouldn't really be having this conversation on KSmrq's talk page; it pings him every time there's an edit and clutters the thing up. --Trovatore 18:08, 30 October 2005 (UTC)

I think this is fine for the discussion, since he is the one who reintroduced the idea of the rename and has an interest in it. Your suggestion is a good one, but again, I can't see how you would ever convince your fellow mathematicians to make such a change. There seems to be a strong feeling among the group that rigourous theoretical mathematics is the only valuable subject, and all others are beneath mentioning. Giving the main page away would upset them no end. StuRat 18:16, 30 October 2005 (UTC)

I thought I did a nice job on the intro myself; how many votes do I get to cast? ;-)

Ah, well. Feel free to canabalize it for parts. As for the picture, I made it as I suggested, with Graphviz — specifically "dot" — and the layout is automatic. It's pretty smart, because if you were actually to draw what you suggested, the lines would be much more tangled. But you could certainly use colors or dash patterns or some such for your purposes. The present source file is trivial:

digraph HasseDiagram {
  graph [ratio=0.75, bgcolor="#ffffff"];
  node [fontname="Arial"]
  "xyz" [label="{x,y,z}"];
  "yz" [label="{y,z}"];
  "xz" [label="{x,z}"];
  "xy" [label="{x,y}"];
  "x" [label="{x}"];
  "y" [label="{y}"];
  "z" [label="{z}"];
  "phi" [label="Ø"];
  
  edge [dir="back", arrowtail="empty"];
  "xyz" -> {"yz"; "xz"; "xy"};
  "yz" -> {"y"; "z"};
  "xz" -> {"x"; "z"};
  "xy" -> {"x"; "y"};
  "x" -> "phi"
  "y" -> "phi"
  "z" -> "phi"
}

I rendered a PNG with Batik to have ultimate control, but Commons accepts SVG directly now if you prefer. Perhaps one image could support all the text; if not, it would be simple to generate all the variations you like. For example, here's one way to show the law of the excluded middle in lattice form:

digraph HasseDiagram {
  graph [ratio=0.75, bgcolor="#ffffff"];
  node [fontname="Arial"]
  "xyz" [label="{x,y,z}"];
  "yz" [label="{y,z}"];
  "xz" [label="{x,z}"];
  "xy" [label="{x,y}",style="filled",fillcolor="#fad1c2"];
  "x" [label="{x}"];
  "y" [label="{y}"];
  "z" [label="{z}",style="filled",fillcolor="#d7cd99"];
  "phi" [label="Ø"];
  
  edge [dir="back", arrowtail="empty"];
  "xyz" -> {"yz"; "xy"} [color="#00b1be"];
  "xyz" -> "xz";
  "yz" -> {"z"} [color="#00b1be"];
  "yz" -> {"y"};
  "xz" -> {"x"; "z"};
  "xy" -> {"x"; "y"};
  "x" -> "phi"
  "y" -> "phi"
  "z" -> "phi"
}

Since Graphviz is open-source and available cross-platform, just grab a copy and play. --KSmrq^T 22:04, 29 October 2005 (UTC)

[edit] Graphviz

So I downloaded graphviz (for Debian stable), but dotty doesn't seem to work extremely well (labels don't show up; right-click brings up a menu but the menu doesn't do anything). I put together a file (for the free Boolean algebra with two generators, p and q) and figured out how to make a PostScript file, but I can't figure out how to get Unicode into the labels, so the symbols don't work. I also didn't see anything that said you could upload .dot files. Anyway here's the source if you want to see what you can do with it:

PS: I made a version without any unicode, a little awkwardly; you can see it at free Boolean algebra. --Trovatore 08:23, 11 November 2005 (UTC)

digraph HasseDiagramFree2 {
 graph [ratio=0.75, bgcolor="#ffffff"];
 node [fontname="Arial"]
 "false" [label="FALSE"];
 "pq" [label="p∧q"];
 "pnq" [label="p∧¬q"];
 "npq" [label="¬p∧q"];
 "npnq" [label="¬p∧¬q"];
 "p" [label="p"];
 "q" [label="q"];
 "piffq" [label="p↔q"];
 "nq" [label="(¬q)"];
 "piffnq" [label="p↔¬q"];
 "np" [label="(¬p)"];
 "pvq" [label="p∨q"];
 "qthenp" [label="q→p"];
 "pthenq" [label="p→q"];
 "npvnq" [label="¬p∨¬q"];
 "true" [label="TRUE"];
  
 edge [dir="back", arrowtail="empty"];
  "true" -> {"pvq";  "qthenp";  "pthenq"; "npvnq"};
  "pvq" -> {"p"; "q"; "piffnq"};
  "qthenp" -> {"p"; "piffq" ; "nq"};
  "pthenq" -> {"q"; "piffq"; "np"};
  "npvnq" -> {"nq"; "piffnq"; "np"};
  "p" -> {"pq"; "pnq"};
  "q" -> {"pq"; "npq"};
  "piffq" -> {"pq"; "npnq"};
  "nq" -> {"pnq"; "npnq"};
  "piffnq" -> {"pnq"; "npq"};
  "np" -> {"npq"; "npnq"};
  "pq" -> "false";
  "pnq" -> "false";
  "npq" -> "false";
  "npnq" -> "false";
  }

Good job. Unicode should be possible in two easy ways. The first is to use a text editor that handles UTF-8; the layout programs are supposed to be happy with UTF-8. The second is to use a placeholder character of the same approximate width during layout, to ask for SVG output, and then to edit the SVG to substitute the desired Unicode or an XML numeric character code. Commons now accepts SVG files directly, if you want to try that. You can preview or render SVG using Batik, or in most cases the latest Firefox (release candidate 1) can directly view SVG files. If you upload an SVG, you are at the mercy of the server's fonts and rendering. If you use Batik to make a PNG, you can use any font, such as Code2000, with any characters you may need. There is a "glyph" feature in SVG that allows you to draw a character, but that would be a painful last resort.

Anyway, looks like you've discovered the joys of GraphViz. I've found its input is easy and its output is appealing. Two suggestions:

1. You might want to kill the parens around NOT p and NOT q where they occur alone (on the center line).
2. If you give the graph a different aspect ratio, the graph may be able to spread out enough so none of the arrows have to curve. (This problem may also fix itself if you get the Unicode working.)

Also, if you do render the PNG yourself, use a resolution like 300 dpi with antialiasing. (Or render even larger and reduce smoothly to get the effect of antialiasing.) The Wikipedia server will create (and cache) smaller requested sizes as needed. This allows both screen and printed output to look good. --KSmrq^T 03:34, 12 November 2005 (UTC)

dot doesn't seem to work correctly with UTF-8, and without the parens around ¬p and ¬q it gave me a syntax error. I think it's basically just a little buggy. "dot -Tpng" produces PNG output directly; that's how I generated the file. --Trovatore 04:22, 12 November 2005 (UTC)

[edit] Gosper

My recollection is that Bill Gosper introduced the idea of telescoping. He is one of the pioneers of computer symbolic mathematics programs, having contributed to both Macsyma and Mathematica, for example. His web page [1] cites A calculus of Series Rearrangements, which might be the place to look. --KSmrq^T 01:52, 3 December 2005 (UTC)

What!!!??? How could he have introduced this idea if his life was so recent that he worked with electronic computers?? Michael Hardy 22:30, 3 December 2005 (UTC)

Series have been around a long time. I'm not intimately familiar with the history of who did what when, and I don't know what Bill would claim was his and what he dug up or adapted. But it's my impression that he was able to do remarkable new things with series, including telescoping — a term I first heard associated with his work. Obviously people had been rearranging series long before him, but perhaps not in the way he did it. These are vague memories including conversations over Chinese dinners from long ago. Examples of his contributions include Gosper's Algorithm [2], which was extended to "creative telescoping" [3]. A more extended discussion of telescoping and Maple is

• Abramov et al. "Telescoping in the context of symbolic summation in Maple". Journal of Symbolic Computation, v38 (2004), 1303–1326. (PDF)

Perhaps that paper, or its references (especially Lafon 1983), can pin down the history of the ideas or the terminology. My bigger point is that the telescoping series article omits important knowledge and references. I still think Gosper is a good place to start looking for more. It's not my specialty, so my comment is just a drive-by shooting on the talk page to stimulate improvements. --KSmrq^T 03:44, 4 December 2005 (UTC)

Gosper indeed did a lot of work on how to handle infinite sums on computer algebra systems. But as far as I know, he "only" made an algorithm that enabled computers to compute sums that mathematicians could already do (given enough time and motivation and a bit of ingenuity). The idea of telescoping sums must be centuries old; in fact, I wouldn't been surprised if it is older than the telescope. I learnt the term in high school, so it is rather basic. -- Jitse Niesen (talk) 04:09, 4 December 2005 (UTC)

Obviously that's a huge "only", like stating the Pythagorean theorem compared to finding a 3-4-5 right triangle. In any case, the Abramov article offers a wealth of content not found in the Wikipedia article. And I'd still like to know when and where the term "telescoping" was introduced. (I'm fairly confident my high school years predate yours, and I never heard the term; by that reasoning, it must be more recent. Or, more likely, the reasoning is unreliable.) --KSmrq^T 05:56, 4 December 2005 (UTC)

KSmrq, all of the sources you cite were published after I graduated from high school (in 1974), and I learned about telescoping series, by that name, in high school, and I think everybody does. And I'm pretty sure telescoping series were used by Euler in the 18th century. To suggest that they were introduced only in the last two or three decades is false and bizarre. Michael Hardy 21:50, 4 December 2005 (UTC)

Yes, I would be very surprised if Euler didn't know about telescoping. (But I don't have any hard evidence.) By the way, I never heard the term "telescoping series" until I came to the U.S., but I was certainly aware of the concept before then. Dmharvey 22:02, 4 December 2005 (UTC)

It does seem commonplace for students of computer science to think that every idea that was known 200 or 2000 years ago was first introduced a couple of years ago and is unknown except in computer science. Michael Hardy 00:42, 5 December 2005 (UTC)

I have absolutely no recollection of learning about telescoping series — nor any series — in high school, so either I've got a missing memory, or not everyone learns about them. In contrast, I definitely remember hearing Gosper talk about them, and demonstrate to me things he could do that, apparently, had not been done before. Maybe this is a difference between what the Abramov article discusses under "classic telescoping" versus "creative telescoping". Again, I don't know the true history of the term. As for computer science myopia, that certainly does not apply to Don Knuth, nor, I think, to Gosper. What I do know is that, at the moment, the article includes no history, and no mention of modern telescoping methods. Instead of berating me, it would be more productive for you, Michael, to take up the challenge of finding an early citation of the term "telescoping"; also, to discuss or cite at least one modern computer algebra algorithm in the article. --KSmrq^T 01:43, 5 December 2005 (UTC)

I just had a look at Euler's "Introductio in analysin infinitorum". It's available online at http://visualiseur.bnf.fr/Visualiseur?Destination=Gallica&O=NUMM-3351. (That's a scan of a 1967 edition, in the original latin.) If you skip to page 47, you'll see what is just recognisable as a discussion about taking the sum of a geometric series. Euler didn't have our convenient summation notation, so it's a bit painful, but it's quite clear he was carrying out a calculation like this one: Of course, he also didn't know how to define convergence properly, so we wasn't thinking about partial sums converging, but at the very least, he's definitely formally matching up the terms with , which I think counts as a telescoping series. Dmharvey 02:19, 5 December 2005 (UTC)

I'm not at all surprised that the technique is in that 18th-century book, but there's also the question of whether Euler used that term. Michael Hardy 02:34, 5 December 2005 (UTC)

OK, I'm going to go way out on a limb and hazard a guess: it's a very modern term, possibly introduced as late as 1910 or so, but perhaps more likely in the second half of the 19th century. Just a guess ... I'll work on it. Michael Hardy 02:57, 5 December 2005 (UTC)

As a starting point: The earliest reference on MathSciNet to "telescoping sum" is MR0086724 (19,232h), a review of a 1957 paper (Brown, Richard H., The solution of a certain two-person zero-sum game, Operations Res. 5 (1957), 63-67). And to clarify: I learnt the term "telescoping series" while I was at high school, but not during regular high school teaching. -- Jitse Niesen (talk) 12:52, 5 December 2005 (UTC)

Gosper is a bright fellow, but I don't believe he was publishing that early; so that would seem to shoot down my broadest speculation. That settled, I'd like to suggest that further discussion and documentation migrate back to Talk:Telescoping series, for the benefit of future editors. --KSmrq^T 18:54, 5 December 2005 (UTC)

[edit] Boolean algebra intro

Hi KSmrq. I think there has been sufficient support expressed on talk:Boolean algebra (with perhaps some minor modifications) for you to go ahead and make your proposed changes to the intro. If for some reason you would rather someone else do it, I'd be happy to. Paul August ☎ 20:24, 5 December 2005 (UTC)

[edit] 0.999... and all that

Hey, check this out. Melchoir 21:20, 6 December 2005 (UTC)

Dear KSmrq.

You have removed some material from the Proof that 0.999... equals 1, calling it distracting crap. I think that is a bad idea. Many Wikipedia readers and editors will "feel" that 0.999... < 1, and if the article only provides formal (to them incomprehensible) proof that 0.999... = 1, and perhaps a couple of informal (and therefore actually quite dubious) proofs, it will not really help them understand anything better. To whom were those paragraphs distracting? To those in the know? I think not; I trust they will be able to see what is what in this article. To the lay reader? I think not; on the contrary. In what sense is it crap? Well, if you think it needs improvement, help us improve it. Will you re-consider, or explain, your deletion?--Niels Ø 15:42, 20 May 2006 (UTC)

kill is not a good edit summary. Please Explain your deletions so their is not Confusion. When removing text that isn't Blatant Vandalism you need to Explain why in the edit summary.--E-Bod 23:05, 22 June 2006 (UTC)

[edit] MathML Characters

Your page listing MathML characters is fun to look at. Its also one of the only places on the web that I've been able to find the "double contour integral" symbol, which I have an inordinate interest in for some reason. Most of the symbols show up fine for me, but for some reason a lot near the bottom are all just question marks. Do you know why this is? I'm still trying to figure out the relationship between wikipedia, TeX, MathML, fonts in general and whatever else might be used here to create characters of this type, so if theres somewhere else I should be looking, please, just point me in the right direction. --Monguin61 02:21, 10 December 2005 (UTC)

I'm replying here for your convenience. Unfortunately, visibility of characters can depend on OS, browser, settings, and fonts. Fortunately, just installing a font is often enough. I suggest trying the Code2000 font. I also find the Mozilla browsers, like Mozilla Firefox, support MathML and Unicode fonts fairly well. --KSmrqT 03:12, 10 December 2005 (UTC)

I'm already using Firefox, installing code2000 did the trick. Thanks a lot. (I don't know if local etiquette calls for me to respond here or on my own talk page, is there a standard I should be following?) --Monguin61 03:37, 10 December 2005 (UTC)

Great, I'm glad that worked for you.

Ordinarily, if you make the post on my talk page I'll reply on my page so the thread of the conversation stays in one place. When the conversation is about an article, at some point it may be better to migrate to that article's own talk page so others can find it and benefit. In this case, I replied on your talk page only because I wasn't sure if you were comfortable using your watchlist. --KSmrq^T 03:50, 10 December 2005 (UTC)

[edit] Kudos

I've been impressed by the quality of your responses on WP:RD/Maths, and in particular your summary of combination and permutation in response to the Statistics question is a gem of condensed clarity. --- Charles Stewart 01:43, 4 January 2006 (UTC)

Thanks. That kind of writing is more work than most people realize. It's gratifying when it succeeds. --KSmrq^T 15:34, 4 January 2006 (UTC)

[edit] Please comment on the current Math Collaboration of the Week

Hi KSmrq - since you listed mathematics as an interest in your user talk, I was hoping you could lend your expertise to the current Mathematics Collaboration of the Week: Multiple Comparisons. Obviously it's a interesting and important topic. We are also in the midst of a discussion as to the distinction between multiple comparisons and multiple testing. Your thoughts would be much appreciated. Let's get a math article up on the front page! Thanks for any help. Debivort 10:16, 5 January 2006 (UTC)

[edit] Pythagorean theorem

The Pythagorean theorem has attracted enormous numbers of proofs. If you think a new one deserves a place in the article, display it on the article talk page and invite discussion. There's a good chance (but no guarantee) agreement will emerge.

As I said, I moved user:Bryanmcdonald's argument to another (earlier) place in the article, and attributed it to him in my edit summary. Unless someone changed it since then, it's there. Michael Hardy 23:31, 10 January 2006 (UTC)

... and now I've just checked. It's still there. Michael Hardy 23:32, 10 January 2006 (UTC)

Different people absorb information best in different ways. I'm a visual thinker. Apparently so is Bryanmcdonald. For me, the picture seemed worth retaining. It's gone. Apparently that bothers him. I can relate.

That said, I don't intend to get tied up in discussions of the article. My intent is to help Bryanmcdonald adapt to Wikipedia, so that he can better represent his own interests for himself without giving up in frustration. I'm not taking sides, nor promising a certain outcome; I'm only coaching. (He was greeted on 20 December 2005.) I expect you might do the same if you didn't have a position in the debate. --KSmrq^T 04:35, 11 January 2006 (UTC)

[edit] Infinitely nested commutators

Hello! A while ago I asked a question on the reference desk about pseudo-BCH formulas. I have another question which I hope you can help me with. Under what conditions does an infinite commutator series exist? I am not sure if I am asking this in a precise enough fashion, but I hope you can help point me in the right direction. Thanks in advance! --HappyCamper 02:37, 8 March 2006 (UTC)

I'm not sure that's a precise enough question. For example, BCH for SO(3) is an infinite series, yet a closed form also exists. The most obvious way the series will terminate early is when there is commutativity. Otherwise, I don't know. --KSmrq^T 04:26, 8 March 2006 (UTC)

[edit] your opinion sought

Hi there KSmrq,

I've been looking back at wallpaper group and thinking that some of the graphics there is getting a little messy. It seems a bit of overkill to have two cell diagrams for every group and a "computer generated" image for most of them too. So I'm thinking of making a new series of images that combines all of these things, to replace all of them. Here's an example of one I tried making today for p31m (gosh it took a while):

Here were some of the things I kept in mind while drawing this:

• Part of the image should be "just the pattern" (in this example, it's the stuff on the right), made up of a simple, hopefully cute asymmetric shape. I started out with a little "alien" and deformed him/her/it in various ways to fit different shaped fundamental domains.
• It should indicate all the symmetries using some easy-to-understand icons. I found that when I was staring at the cell diagrams on the current version of wallpaper group it took me quite a while to work out what was going on. I'm hoping that the arrows here make it easier for people that are less familiar with the setup.
• It should indicate both a fundamental domain and a lattice cell.
• The whole series should be uniformly designed; matching colours, icons, and as far as possible, a single repeating motif (e.g. the alien).

I was wondering if you would like to offer any constructive/destructive criticism before I dive into all 17 groups. Dmharvey 20:16, 5 April 2006 (UTC)

Sure, I thought about this myself some time back, and did some experiments.

• One difference in approach is that where you incorporate artistic expression, I deliberately chose to be graphically spare. I was thinking, in part, about something like the icons used in Kali.
• The example you provide strikes me as "busy". For a decorative pattern, that's fine. When trying to see and understand symmetry markers within the image, that's an obstacle.
• As for the markers themselves, I'm assuming a flat double-headed arrow is reflection and a "seesaw" is glide reflection. I never found or invented a glide reflection symbol I really liked; you can see one attempt here. You do use different colors for different rotation centers (which is good), but your markers do not indicate the order, here both three-fold.
• I'd prefer to include two translation arrows as well, but almost everyone seems to omit these as just too much.
• The fundamental domain helps understand Conway notation; the lattice cell helps with crystallographic notation. So that's all good. But, of course, these require introducing two more graphic conventions in an already busy image.
• In my experiments I did not alter the motif to fit a fundamental region. I found it informative to see how the same motif produced different patterns under different symmetry group actions. And notice that the alteration is redundant, since you've already got a notation for the fundamental region.
• It looks like you've been using Inkscape. While it does have a symmetry tool and gives access to a broad range of SVG facilities, I found that Tess was better for me. Luckily the version I began with did not disable saves for unregistered copies (it merely nagged); the current version does, with a $36 registration fee. Besides the specialized interface, Tess also exports SVG; you could mangle its output further in Inkscape. The lovely markers it displays in its graphical interface do not appear in the exported image, so some post-export mangling may be inevitable.
• One thing I contemplated, and dabbled with a little, was changing the shape (translation lengths and angles) for the groups that allowed that. The freedom (or not) to do that is one of the distinctions among groups. (Tess supports this using the selection tool, and conveniently lists the more flexible groups first.) Two problems I found were that it conflicted with using a common motif, and that it required more design decisions.

I'll email you one or two of my experiments for your amusement. --KSmrq^T 05:53, 6 April 2006 (UTC)

[edit] Part 2

I haven't got your email yet, but just a few quick queries/comments while I wolf down breakfast.

• When you say "busy" are you referring to the motif itself, or the overall impression of the image?
• Yes glide reflections are very tricky. I thought about this for a long time, and I'm not totally happy with the result. One difficulty with your solution is that the reflection arrows and glide reflection arrows are a bit inconsistent, because the "direction of the arrow" means something a bit different in each of them. On the other hand, mine really require two arrow heads to work, which clutters things up more.
• I guess I altered the motif because I didn't want large swathes of empty space. In the p31m example above, I realised later it is possible to select a kite-shaped fundmental domain which more comfortably fits a "blob-like" motif.... I haven't yet thought about whether that is possible for the other groups.
• I was using Inkscape, but not with the symmetry tool! I cut and pasted things myself. I was vaguely aware that such a tool existed, but I was so busy learning how to use Inkscape, I never got around to trying it. Besides, I'm a bit of a control freak :-)
• Re: different shapes for rotations: good point.

Dmharvey 12:23, 6 April 2006 (UTC)

OK I got the email (it came down in my daily spam digest :-)). My computer can't run EXE files but I knew my wife's computer was good for something :-) There's a couple of nice ideas in the files you sent.... I'm going to think about it for a while and try merging some of what you've done with some of what I was doing before, and see what happens. Dmharvey 20:08, 6 April 2006 (UTC)

And I've sent you an email with more stuff in it. Dmharvey 22:08, 6 April 2006 (UTC)

Got your email.

The whole image is busy, which means there are so many features distracting the eye that it sounds like a crowd rather than a chorus, if that audio analogy makes sense for you.

We know from Conway notation that we have as many as five essential markers for a fundamental region, for group *2222 (pmm). We also have other symmetries to show, such as the glide reflections in 22x (pgg). Also we must delineate a fundamental region and a cell. So the motif itself and any graphical touches other than essentials must be handled with care lest the eye be overwhelmed with visual clutter. All those arrows, lines, edges, dots, curves, corners, colors, and fades are hard to take in.

Here are some possible clutter reductions to explore.

• Simplify the motif. Does it need an eye and a mouth and a stomach? Try losing the eye.
• Don't use a blue marker and a blue motif; colors are symbolic.
• Invent a simpler rotation marker without a separate center and arrow. (A spiral galaxy?)
• Lose the arrows in the individual groups, but present them once in an image explaining the simple graphical markers.
• Color the arrows to match the centers.
• Color-code every marker, so we have more than shape.
• Think about line weights and dashing patterns; should they be more distinct or more unified?
• Do we need to tile the markers, or would marking a single cell suffice?
• Is the cross-fade effect confusing or helpful?
• Would it work better to position the cell/region in the center of the image, or to arrange not to cut off a corner?
• Can we tempt a graphic artist wikipedian to lend an eye?

Many of my images draw on a basic color vocabulary from vision theory:

1.  ◼  #000000, Black
2.  ◼  #ffffff, White
3.  ◼  #bc1e47, Red
4.  ◼  #009246, Green
5.  ◼  #0081cd, Blue
6.  ◼  #fec200, Yellow

These are opponent colors, so for most people they are bold and distinct. (Other basic named colors include pink, orange, purple and brown; but I haven't used these.) One drawback of using opponent colors is that for some people the red and green look identical; this is less of a problem when following the design rule that color should always be a supplementary cue. --KSmrq^T 00:58, 7 April 2006 (UTC)

Here's another attempt, which I was mostly done with before I got to read your last comments. Bit tired now, but let me know what you think.

Dmharvey 03:00, 7 April 2006 (UTC)

[edit] Part 3, color palette

Thinking aloud… Suppose each order of rotation center gets a different hue; here's a color palette experiment:

 ◼  #000000, Black

 ◼  #ffffff, White

 ◼  #bc1e47, Red

 ◼  Red0,  ◼  Red2

 ◼  #009246, Green

 ◼  Green0,  ◼  Green2,  ◼  Green3

 ◼  #0081cd, Blue

 ◼  Blue2

 ◼  #fec200, Yellow

——————————

 ◼  #a125bb, Purple

 ◼  Purple2

 ◼  #ff4500, Orange

 ◼  Orange2

 ◼  #77250a, Brown

 ◼  #ff779a, Pink

Use greens for 2-fold, reds for 3-fold, blues for 4-fold, and yellow for 6-fold. It might work, with oranges for reflections, purples for glide reflections, light and dark gray for the cell and fundamental region, and a black and white pattern. --KSmrq^T 07:13, 7 April 2006 (UTC)

[edit] Part 4

Here's that one again with some of the colours you suggested. I agree the black motifs are an improvement. In my opinion it is easier to see the group actions on this last image. However, I find it always relatively difficult to spot the glide reflections for this particular group, they're not quite as in-your-face as for some of the other groups. I wasn't totally sure which orange and purple to use for the axes; I just chose the ones labelled "purple" and "orange" from list of colors. Perhaps the purple is a little too dark. Also plain greyscale for the lattice cell just didn't work for me, I retained the slightly greenish-brownish-grey. I've killed the dotted lines, again they seem to increase busy-ness (business?). I'll have to try one or two more of the groups before we get a clearer idea how things are really looking. If you want to mess with the colours, each type of object is in a separate layer, so you can just select the layer in inkscape and "select all". Your thoughts? Dmharvey 12:30, 7 April 2006 (UTC)

Oops they were supposed to be red not green. Dmharvey 21:15, 7 April 2006 (UTC)

Here's one for p2. Also I've fixed up the colours for the previous one; I changed the triangles to the reds you suggested, and changed the axis colours too, but the orange looked too much like the red so I added a bit of green to it (might need to flush cache to get it loading). Dmharvey 03:17, 8 April 2006 (UTC)

And here's pmg. For some reason it's harder to tell apart the reflection and glide reflections colours in this one, but it didn't seem to be a problem in the previous one. How do they look to you? Dmharvey 03:55, 8 April 2006 (UTC)

Try switching colors, to purple for reflections and orange for glide reflections. Also, orange is really bright, so maybe pink would work better. The Conway notation includes ** and xx, so we probably should have two shades of each reflection and glide reflection color.

Try losing the black outlines for the rotation markers. Also, try smaller markers.

I'd still like to try the "spiral galaxy" idea, with the number of arms showing the rotation order.

Again the "eye" is distracting; a shape alone is cleaner.

The scale of the image makes a palpable difference in readability. This suggests a graphical ploy: Show the full pattern with a number of repetitions, but overlay a single cell at a larger scale to show the markers, like a magnifying glass effect.

The fade effect on the pattern produces a gray that conflicts with the idea of showing the cell in gray. Using a colored cell alters the appearance of the marker colors, so I'd still prefer a gray cell. I'll have to think about what might be done.

My overall impression is that the more recent attempts are less pretty, but more perspicuous, that the first one. --KSmrq^T 08:13, 8 April 2006 (UTC)

[edit] Part 5

I tried a bunch of things, and found myself converging on what you emailed me :-)

• I like the spirals. Mine have a few more straight lines.
• I've put dotted lines for the glide reflections, because otherwise the only thing distinguishing them from the reflections is the colour.
• I've noticed (as you probably have) that it helps not to have the motif as large as it possibly can be, because then it runs into the spirals. So I made them a little smaller, it works much better that way.
• What do you think about putting thin black outlines around the spiral icons, to help separate them from the background colour? Already that darker green doesn't work well against the dark grey. The yellow doesn't work too well with the lighter grey, but I don't think that's a problem because there is never a sixfold rotation in the interior of the lattice cell anyway.
• I tried the "magnification" idea for a while, but it really didn't work. I think partitioning things into two separate images as above is the best solution.
• I'm still not totally happy with the colour selections. I haven't been consistently using the ones you listed above.
• We need to think a bit about the overall aspect ratio, and how this will impact on the article layout.

Dmharvey 02:59, 9 April 2006 (UTC)

And here's p4.

Dmharvey 04:02, 9 April 2006 (UTC)

---

And here's another attempt at p6m. I quite like these ones.

• It occurred to me that if the rotation markers had a little black around them they would be easier to see. Hence the shadows. The shadows also mean that we have a bit more flexibility with colours, because for example it would be quite okay for a reflection or glide reflection axis to share colour space with the rotation markers.
• The pattern on the left has a slight "poor man's 3-d effect" applied, makes it a bit easier on the eyes I think.
• Something else I've noticed is that reflection axes never pass through the motif (although glide reflections might). Maybe we can turn this to our advantage somehow.

Dmharvey 02:07, 10 April 2006 (UTC)

[edit] Part 6

From Wikipedia:Picture tutorial#Thumbnailing:

• But 'thumb' also automatically resizes a large picture into a smaller display size, with an option for the user to click on the image and see the original large version. Because different people work to different screen resolutions, your preferred size of thumbnails can be set in special:preferences under "files". The default, which is also used for logged-out users is 180 pixels (px), but you can choose between 120px, 150px, 180px, 200px, 250px, and 300px sizes. If an image is smaller than the thumbnail size you specified then it is displayed at 100% resolution, i.e. its natural width. Generally speaking, thumbnails are the best way to display images.

So it looks like 180px is the default thumbnail width, with aspect ratio preservation giving height. The originals for the current right-hand images, by Martin von Gagern, are consistently 744 wide by 425 high, about 1.75 width-to-height aspect ratio.

However, I'm tempted to go with ISO 216 aspect ratio, 0.707, such as B5 at 176×250, with originals as B1, 707×1000. Only I mean pixels instead of millimeters, of course. Then if we juxtapose a pattern and a structure diagram, we get the same aspect ratio, only on its side. And 1.414 is fairly satisfying, not far from 1.5, 1.618 (golden), 1.333 (old TV), and 1.778 (HDTV). (Here's an illustration.)

This is only a thought; I'm never sure what to do with aspect ratios. But again, I've also noticed that size dramatically affects perception. Unfortunately, most of my experiments have looked best large.

A few thoughts on your recent attempts:

• The motif looks too similar to the spinners; I prefer my "whale" shape, a more poetic d/b/p/q. Its curvaceous contour avoids confusion.
• I've been keeping the whale the same, but filling in different triangles for each group, so as to achieve a pleasing pattern/background ratio without too much empty space.
• The "shadow" does make the spinners pop; might be something to keep. But I think your spinners are a little too simple, especially the 2-fold shape, which just doesn't spin for me as well as mine. My arms were accidently too short, which I've adjusted in my more recent trials.
• Colors are a nuisance. It's especially bad with 2-fold (four shades) and 3-fold (three shades). I've changed my mind about using both green and blue for spinners; they don't mix distinctly. Instead, I'm using 6-fold yellow, 4-fold purple, 3-fold red, 2-fold green. For reflections, orange, and for glide reflections, blue; I haven't yet tried two shades of each. The difference in lightness between orange and blue may be enough to distinguish them even without dotting (which I still find adds clutter).
• I've thought about ways to use 3D hints, such as drop shadows and 3D lighting hints. At present, Firefox SVG doesn't do 3D light effects, so I'm reluctant to incorporate these, despite their visual appeal. Either the pattern or the structure markup could use 3D allusions to distinguish it from the other.
• I like to include the spinners in the pattern itself. It's prettier, not too cluttered, and really brings out the rotation symmetry.
• I've been clipping the glide/reflection lines against the cell, rather than fading, only with the clip region expanded 50%.

By the way, having one huge section was getting painful, so I've partitioned it into subsections for my convenience. Same content. --KSmrq^T 05:56, 11 April 2006 (UTC)

I'll try some of these things in the next iteration. For now:

• check out http://commons.wikimedia.org/wiki/User:Dmharvey/Wallpaper_testing for a first layout trial
• I don't know what you mean by the clipping comment.

OK, I understand what you mean about clipping now. I don't think the clipping is too relevant for the layout I have in mind, since one image will have the cell diagram and one image a larger scale pattern, but we can have another look later. Dmharvey 22:36, 12 April 2006 (UTC)

• I have found the most difficult colour issue is with the reflection/glide reflection axes. You mentioned that you still haven't tried two shades for each one. Well, you should try it!... when I try it I go insane. It's extremely difficult to find two sufficiently separated colours each with two shades, which all simultaneously look nice and clear against two different background greys! (The colours that seem to look best against the greys are the orange/yellow kinds.) That's the reason I've been sticking to the dotted lines. On the other hand, I agree the dotted/dashed lines add clutter. Another approach might be: make the reflection axes thick, and the glide reflections thin, and use the same two shades of orange/yellow to distinguish the families of reflections (or glide reflections).

I feel like we're starting to get somewhere! Dmharvey 14:07, 11 April 2006 (UTC)

[edit] Part 7

Do these spin enough for you? Or are we getting too cluttered again?

Dmharvey 18:06, 12 April 2006 (UTC)

---

More tweaking:

Dmharvey 22:35, 12 April 2006 (UTC)

---

Another try at marking out the axes:

Dmharvey 19:38, 16 April 2006 (UTC)

No joy; I like the previous version better than this. The new attempt is full of lines and curves, and lacks contrast. --KSmrq^T 19:51, 16 April 2006 (UTC)

[edit] Part 8

Then here's another of the previous one with a few changes:

• Axes a bit thicker
• Spinner colours changed a bit, some extra ones thrown in to show the full range
• Reshaped the 180 degree markers, try to give them a little more "spin"
• Shaped the 180 degree marker shadows, a bit more elongated
• Adjusted shadow opacity to compensate for different lightness on each marker (i.e. the darker markers are getting deeper shadows, lighter markers shallower shadows)

What do you think? Dmharvey 22:14, 16 April 2006 (UTC)

I think p6m looks pretty no matter what we do. :-D

Aside from that, I've been thinking about our options, and may have a winning improvement. We've been trying to make four green 2-fold spinners that all look identifiably green, show clearly against the different shades of background, are distinguishable from each other, and are clearly not any of the other spinner colors. That's asking a lot, and it's no wonder we have a hard time. On the other hand, we've had very little trouble making spinner shapes. Some of our attempts spin a little better than others, but all show the necessary symmetry and all read fairly well. So: suppose we distinguish distinct rotation centers of the same color, not by shades of the color, but by spinner shape.

That still leaves the glide/reflection markers to shape and color, but could simplify our task considerably.

I have some other thoughts and experiments (such as faint triangles), but those can wait. --KSmrq^T 02:11, 18 April 2006 (UTC)

That's a good idea. I think more than two shapes might be problematic though. Perhaps two shapes and two shades? We need four distinct 2-fold spinners for p2 and pmm, three of them for cmm, and three distinct 3-fold spinners for p3 and p3m1. (All the others we need at most two of any type.) Where there are three classes, it's a bit annoying with two shapes and two shades, because you have to throw one out which messes up the symmetry of the choices, but on the other hand, if you look at the locations of the spinners for cmm, p3 and p3m1, there's a good case for selecting an "odd one out". So I think that might work. I might try grabbing your spinners and my more recent ones and see if I can fudge them to look as different as possible. Dmharvey 02:22, 18 April 2006 (UTC)

The 4-fold spinners pack the "blades" most tightly, so p4m is a good test case to discriminate the first two shapes. Then p3 displays the range of 3-fold spinners to see how the third shape works, and pmm has four distinct 2-fold sites. Let's try first separating the sites with shape alone, then fall back on shade if we must. --KSmrq^T 13:49, 18 April 2006 (UTC)

I think you're right, something like this will work. These are just the first couple of designs I came up with, already it's not too hard to distinguish them, even on the smaller image. And it's so much nicer with the more uniform colour scheme (but I didn't think carefully about the specific colours on this example). I might try to make a few more spinners... perhaps you could also submit a few designs and we can pick a few to run with? Dmharvey 02:55, 19 April 2006 (UTC)

I've seen many illustrations of tilings in my day, but these are exceptionally attractive! Good work!

BTW, KSmrq; did you see that I recently mentioned that in light of Jimbo's recent call for a focus on quality over quantity and the creation of a new Advisory Committee as per my talk page (no idea if there is any cause and effect there), I have been considering a cautious return to content creation in re group actions, etc. Unfortunately, Asmodeus has recently expressed an apparent intention to challenge all my edits on the grounds that I am "personally involved" in group actions, tilings, whatever. I don't think the community will support that kind of nonsensical accusation, but its kinda sad to se things get down to this level.---CH 22:52, 14 August 2006 (UTC)

[edit] Edit to manifold

I understand your point, but in...

• A sphere can be treated in almost the same way as the circle. In mathematics a sphere is just the surface (not the solid interior), which can be defined as a subset of R³

I see why the surface is a subset of R³, and why one would talk of a topological sphere and just call it a sphere, but that is a rough transition to a sphere is two-dimensional. Did we do away with surface too quickly for clarity's sake?

StrangerInParadise 08:48, 10 April 2006 (UTC)

[edit] Function, math writing style

Hi. I noticed you reverted my changing of "we" in the function (mathematics) article, citing style guidelines. I was wondering which style guidelines you were referring to. I'm fairly new, so I probably missed them. What I saw was in WP:MSM where it says:

Mathematics articles are often written in a conversational style, as if a lecture is being presented to the reader, and the article is taking the place of the lecturer's whiteboard. However, an article that "speaks" to the reader runs counter to the ideal encyclopedic tone of most Wikipedia articles. Article authors should avoid referring to "we" or addressing the reader directly.

It mentions that using "we" can make difficult topics easier to undertand, but it seems like taking out the "we"s here makes the article sound more like an encylopedia without affecting ease of comprehension. Please let me know what you think. Thanks. Asdfqwe123 20:07, 15 April 2006 (UTC)

Wikipedia has a daunting amount of stuff written about how to edit. The guideline I'm referring to is, fortunately, in a fairly prominent place, Wikipedia:Manual of Style#Avoid self-referential pronouns. It's impossible to tell someone exactly how to write; obviously we'd like to say "Write well." I prefer to use "we" when it avoids stilted language and passive voice; I prefer to avoid the "royal we" and the personal "we". Hope that helps. --KSmrq^T 00:09, 16 April 2006 (UTC)

[edit] Proof_that_0.999..._equals_1

I realize that the balance between an informal style and accuracy is difficult. I may not have attained it; but you appear to be assuming both ignorance and bad faith. This is understandable on such a page, but (unless I flatter myself) neither is correct. Please stop, and discuss. (Please reply on my page; I dislike watching other people's Talk.) Septentrionalis 19:37, 19 April 2006 (UTC)

Thank you for your assurances of good faith; and it is nice to know that graduate work in algebra has left some traces of knowledge of the subject. Septentrionalis 21:26, 19 April 2006 (UTC)

[edit] Fixed-point

Hey- I hope I didn't rub you the wrong way. I've gone back over what I wrote and can't figure out why you took it badly. (I guess I should "tread carefully" when writing about hyphens?) I really would like you to clarify your proposed convention for the spelling. I (and others) will need to understand it in order to implement it. Of course I don't want to know why it makes sense, and I don't think it's wrong- it probably doesn't "make sense" in any meaningful way, and as a convention it can't be wrong or right. I just want to know how it works, so I can do it. Staecker 10:29, 2 May 2006 (UTC)

I must be doing something wrong if I left the impression that I was annoyed with anything you said. I'm fine. Are you familiar with the difference between "descriptive" and "prescriptive" linguistics? One says "here's how people talk" and the other says "here's how people should talk". When I talk about hyphenating the adjective version, I'm being descriptive, and documenting an established convention with support from both Wikipedians and, say, The Chicago Manual of Style. However, when you say the current list of theorem names is inconsistent, I completely agree. I would change each one to use "fixed point", open (no hyphen). The article on hyphen explains when to include the hyphen, and I have almost nothing to add. The reason I raise the point is so that we do not have one editor quite correctly using the hyphen in an appropriate context, and another reverting it per "convention". Think of British-American spelling wars, such as colour/color. Since you proposed a sweeping change (mostly good) to remove hyphens, I thought it essential to include the caveat. --KSmrq^T 20:44, 2 May 2006 (UTC)

[edit] Common sense

I'm not sure, or I wouldn't have edited it. Why is it clear? --VKokielov 11:11, 3 May 2006 (UTC)

What I mean is that it wasn't obvious to me that 0.101001000 isn't a rational number.

Precision is important there. --VKokielov 11:19, 3 May 2006 (UTC)

Please discuss articles on their own talk page. Not only does that allow interested parties to be aware, but it makes it obvious which article is being discussed. Thanks. --KSmrq^T 18:57, 3 May 2006 (UTC)

[edit] Weather and chaos

In Wikipedia:Reference desk archive/Mathematics/April 2006#Chaos Theory, you write:

It is a distracting cheat to introduce quantum mechanics. One of the intriguing facts about chaos is that it can occur strictly within that paragon of determinism, Newtonian physics.

But my point was not about chaos in general, but about the specific example of weather, which was the given example in the thread. Weather is not deterministic. Or at least I believe it is not deterministic, for the reasons I explained there. --Trovatore 21:28, 5 May 2006 (UTC)

The original question from Cosmic girl was about chaos and determinism, not weather; the latter was introduced in the first reply by Gandalf61 through the link to butterfly effect. Our best physics models today have quantum uncertainty as an unavoidable component, so I would argue that at that level any physical system, including weather, is not deterministic. Yet the effects of quantum fluctuations seem to be small enough that our predictions of planetary orbits in the solar system, for practical purposes, are deterministic. Binary stars, by contrast, often do cause chaos at the same level of simulation. What I refrained from saying on the reference desk is that our models and data for weather on Earth are so crippled that we can only guess at determinism. Contrast local weather reports, barely accurate for a day or two, with planetary orbits, accurate for centuries. I think it is helpful to keep the clean mathematics of strange attractors, chaotic dynamics, and bifurcation theory separate from the messy intrusion of quantum uncertainty, poor data, and speculative models. That was the point of my "cheat" remark. --KSmrq^T 00:43, 6 May 2006 (UTC)

Well, perhaps. But I think the odds-on-favorite guess has to be that weather is nondeterministic, not just microscopically but at the level of "will it rain in Dallas on the night of July 20, 2050?". There are a lot of people who seem to have the idea that quantum indeterminacy doesn't apply to macroscopic systems. I think that's nonsense. --Trovatore 02:51, 6 May 2006 (UTC)

Foolish them. Macroscopic quantum effects, such as quantized vorticity in superfluids, have already been demonstrated, and Schrödinger's cat is a standard construct exhibiting macroscopic indeterminacy, so it's hard to support an argument to the contrary. --KSmrq^T 03:36, 6 May 2006 (UTC)

Yeah, but these are somewhat exotic. Weather OTOH is maybe the canonical example of a phenomenon common to everyone's experience. I think a lot of people have not internalized the generalized indeterminacy of everyday life. --Trovatore 20:43, 6 May 2006 (UTC)

[edit] here's your barnstar

Hey, thanks. My first barnstar! :-D --KSmrq^T 19:59, 7 May 2006 (UTC)

[edit] WP:RD/Math#caculate_displacement

Hello. I've seen many of your helpful responses at the RD but I feel that your comment:

This sounds like a possible question for a basic trigonometry class, except for a few real-world details. Doesn't it seem peculiar that a company would employ someone to supervising a massive and expensive job like drilling to 10,000 feet (3 km) without adequate training to answer a question like this?... (my emphasis) was at best condescending to a first timer and probably a turnoff for any future involvement here. Also, I don't think that it was in the spirit of your User page declaration: In my interactions with others, I hope to exhibit compassion for people, enthusiasm for their contributions...

These are my personal observations and please feel free to ignore them if you wish, I just wouldn't sleep well leaving them unsaid. I truly respect your work here and learn a lot from your responses. Regards and cheers from hydnjo talk 22:34, 12 May 2006 (UTC)

Please feel free to delete this section; we just wanted you to read it. hydnjo talk 22:41, 12 May 2006 (UTC)

Greetings, and thanks for stopping by to comment. I agree, my comment could be read as condescending. It could also be read literally, as an observation that a massive deep drilling operation is so expensive it would be absurd to not have the sought expertise in-house. Scan over the questions on the page, and notice that we regularly get thinly disguised homework questions. I did not flatly accuse the poster of deception; instead I raised some natural suspicions. In fact, this still strikes me as incongruous, that someone could be doing this for ten years and be in charge of an operation of this magnitude and not have the knowledge being requested. If this person is serious, and has that much experience with juggling difficult people and challenging circumstances, my skepticism is not likely to be a major obstacle. And I think my second response made it clear I am willing to cooperate with a serious inquiry.

I'd rather occasionally guess wrong than turn off my brain and do kiddies' homework for them. Sometimes I'll ignore the question; sometimes, as here, I'll challenge it. Other times, I'll offer hints without giving a full solution. In my experience the serious questioners come back, and I can apologize if necessary. In the words of Finley Peter Dunne, "Trust everybody, but cut the cards." --KSmrq^T 02:50, 13 May 2006 (UTC)

I do understand your perspective regarding your first response to Les' question but felt a twinge of discomfort about it which I let slide. After reading his detailed response however, I felt that "getting it off my chest" would be best for my peace of mind. Your subsequent response was comprehensive in all respects except for your continuing concern for his (or his company's) lack of resources for dealing with such a seemingly simple problem. I can tell you from personal experience that some of the best "hands-on" guys can come with unimaginable deficiencies which they conceal in unimaginable ways and that was what my lingering concern was about. I think that the situation was handled deftly by all and I look forward to your's and others' reasoned and sometimes humorous responses. And, point taken about FPD's quote. ;-) --hydnjo talk 19:13, 13 May 2006 (UTC)

[edit] Psychic

Hey KSmrq, I just noticed you changed the Psychic page and marked it down as a minor edit, when you took out three paragraphs and replaced it with something very different. Those three paragraphs were logical criticisms of James Randi's challenge. I'm not familiar with the challenge itself, so I find it difficult to comment on the validity - I can only say that they were congruous. Instead, you quoted Randi's FAQ, the quote seemingly mocking psychics - seems like this is going to drive the 'believers' round the bend, and there's a pair at least hanging around there. I find it difficult to judge the validity of including either text, particularly because I'm unsure what Wikipedia policy amounts to on pseudoscience. I just reckon that you've probably made a difficult situation worse, and you didn't say anything on the talk page, and set a fairly significant error as minor. Can you explain it to me please? fel64 20:59, 2 June 2006 (UTC)

Sorry about the "minor" tick; it started that way. When I first glanced at the article I was looking for a link to use in a discussion with an off-hand mention of "psychic hotline", for which this was the best I could find. Short as it is, I immediately noticed some newbie wiki markup mistakes, capitalizing the names of linked topics. So I began an edit, which really was minor, simply to fix those caps. In the process of doing that I noticed the paragraph on the challenge. What I should have done is two separate edits, for different purposes; but instead I combined them and inadvertently left the minor tag set. Bear in mind this was all a distraction from the topic I was originally writing about elsewhere! I'll comment on the talk page about the larger change. Thanks for calling this to my attention. --KSmrq^T 23:37, 2 June 2006 (UTC)

Thank you very much. That explanation was extrememly well written and argued, and the mistake you made is so trivial I felt fairly silly mentioning it - no need to worry on that account.

fel64 14:21, 3 June 2006 (UTC)

[edit] Changes to the signature program article

Hi KSmrq,

I noticed your changes to signature program. I've appreciated the addition of MinRay and, of course, I agree that these programs are "terse", not "optimized" :-) You may find some comments in the talk page and on Wikipedia:Reference_desk_archive/Science/April_2006#One Line C Program Signatures, which is where the article actually originated. I think you can create an autonomous entry for MinRay, and link to it from the See also section of obfuscated code. Also you could add Paul to the List of famous programmers (maybe, please check if there are criteria for inclusion; I know him, so I think he is famous :)).

Cheers,
—Gennaro Prota^•Talk 14:11, 7 June 2006 (UTC)

[edit] Help desk

Thank you for answering my question about Macs and PCs. :) --Alexignatiou 12:17, 10 June 2006 (UTC)

My pleasure. Apple Computer has created quite a buzz by opening up the possibility of dual booting. Should be fun to see. --KSmrq^T 21:24, 10 June 2006 (UTC)

[edit] Surface Normal Outward Normal Left and Right hand rules

Hi KSmrq Re: Article Surface Normal

The word "outward" was edited out of the caption of the image with the advice to stay away from that adjective. However S. P. Timoshenko, recognized as the father of Engineering Elasticity, in his book Theory of Elasticity uses the symbol "N" to represent "outward normal to the surface of a body" The images in the book showing normals are exactly identical to the image in the article.

If an outward normal is to be recognized, shouldn't an inward normal be also recognized? The inward normal vector represents a pressure

If one of the two normals is determined by the Right-hand rule, isn't the other normal, in the opposite direction, uniquely determined by the Left-hand rule?

If you do not mind would you kindly respond Subhash 01:04, 17 June 2006 (UTC)

Retrieved from "http://en.wikipedia.org/wiki/User:Subhash15/Trial2"

I am happy to respond.

The title of the book refers to the "surface of a body", which a mathematician might paraphrase as the boundary of a solid in 3D. Such a solid has a well-defined inside and outside, so the terms "outward" and "inward" can have meaning for the surface. However, mathematicians deal with many surfaces that are not boundaries of solids, including some for which it is demonstrably impossible to distinguish or define "outward" and "inward". A mundane example is a triangle in space; which side is which? But the triangle still has two sides, which is not always so. For example, the famous Möbius strip, a cylindrical strip with a half twist, has only one side. An engineer would never encounter such a surface as the boundary of a solid, but mathematicians encounter them often. Elsewhere in engineering the mathematician's view is needed, so please don't be mislead by one special case.

I am responding here because I do not monitor the talk page of the surface normal article, but in future you should conduct such discussions where all interested parties can see, learn, and participate, on the article talk page. --KSmrq^T 04:28, 17 June 2006 (UTC)

Actually, I will no copy this at talk:surface normal and let us continue there. Maybe some people will want to join. Oleg Alexandrov (talk) 07:56, 17 June 2006 (UTC)

[edit] Admin?

Hi KSmrq. You have been here for more than one year now, I've always seen you exhibit sound judgment, and I think you have a good grasp on how Wikipedia works. Would you like to be an admin? Being an admin does not mean more duties or anything, but I suggest you give some thought to #1 of the "Questions for the candidate" asked of each nominee at Wikipedia:Requests for adminship. Wonder if you would consider me nominating you. Oleg Alexandrov (talk) 08:08, 17 June 2006 (UTC)

Thank you very much for your support. I'm much more interested in content and community than in administration. That is, I like to see inspiring, informative, factual, and well-written articles, and a communinity that works together to that end. And I enjoy the reference desk. Dealing with vandalism and the like is one of my least favorite roles. How do you think being an admin might further my goals? I can see that it might give my voice greater weight in some discussions, but if I wanted more weight I wouldn't use a pseudonym. :-) --KSmrq^T 10:09, 17 June 2006 (UTC)

Nobody likes to deal with administration :) (and most admins don't :) The extra tools can be helpful to delete a page if one has to (to move a page onto an existing redirect say), to block an occasional persistent vandal or to delete occasional nonsense pages (and the quick one button vandalism revert).

So yeah, being an admin does not add much, and to be frank, the one week period when they vote for you can be stressful. But hey, a few more tools in your toolbox may not hurt. :) See for example the way Lethe answered the questions (and good good support) at Wikipedia:Requests for adminship/Lethe. So overall candidating for admin is no big deal, but I would of course understand if you'd prefer not to go for it or not at this time. Oleg Alexandrov (talk) 17:25, 17 June 2006 (UTC)

[edit] Your reverts to Proof that 0.999... equals 1

Could you please explain why you seem to be periodically reverting other users' edits without explanation? If the proof I wrote and Mets501 fixed was incorrect, please explain why. Supadawg - Talk 23:55, 20 June 2006 (UTC)

Apologies, missed your comment on the talk page. Will be replying there shortly. Supadawg - Talk 23:56, 20 June 2006 (UTC)

Please refrain from undoing other people's edits repeatedly. If you continue, an administrator may block you from editing Wikipedia under the three-revert rule, which states that nobody may revert an article to a previous version more than three times in 24 hours. (Note: this also means editing the page to reinsert an old edit. If the effect of your actions is to revert back, it qualifies as a revert.) Thank you. Kevin_b_er 00:12, 21 June 2006 (UTC)

I'll take my chances. I am quite familiar with the three revert rule. The page was essentially trashed (hopefully by mistake), and if you had merely read the paragraph above your comment (and also checked the relevant talk page) you would realize that the revert of my revert was a mistake by a user who did not know what he was doing. The three revert rule does not apply in a case like this. Just curious: I've never seen your name before, and wonder how you came to notice this series of events. --KSmrq^T 00:19, 21 June 2006 (UTC)

'Scuse me? I know exactly what I am doing; I've been editing for two years now. And yes, the three revert rule does apply, as your reverts were undoing other people's work. Supadawg - Talk 00:33, 21 June 2006 (UTC)

No, you missed my comment on the talk page. Let's sort things out there. --KSmrq^T 00:41, 21 June 2006 (UTC)

[edit] Talk:Bernard Haisch

Thanks for your comment! After all my work to try to address his concerns and help him as a WP newbie, it has been disappointing to see his reaction. He has just left a message in the user talk page of ObsidianOrder (talk • contribs), who also seems to have published on Stochastic electrodynamics saying that has emailed Wikimedia; see also Talk:Theory of relativity for a similar threat from User talk:Der alte Hexenmeister, another newbie who I have been trying to mollify without positive result. All in all, I was beginning to feel a bit disgusted, particularly since I had a bad experience with Jack Sarfatti in which it was not clear to me that the WP community was aware of how unfair Sarfatti's charges against me were (I made the mistake of trying to help him as a newbie too, which is hard to verify now since Sarfatti munged all the relevant talk pages so badly by spamming in rants over the comments of others.)

Anyway, I am taking a break from the articles Haisch has been arguing with me about, including Stochastic electrodynamics and Journal of Scientific Exploration. At some point, he will probably become unhappy with other articles too, such as Polarizable vacuum and Zero-point energy. Unfortunately, he truly seems convinced that I am trying to perform a "hatchet job" on him, which is not true at all, as my efforts to work with him show. I am still willing to try to work with him on those articles, which probably could use some improvement, but I can't do that until he calms down enough to discuss changes reasonably. If you have time, it would be helpful if you try to persuade him that WP has a content dispute resolution process which works pretty well. I think he really does not recognize that his edits are POV-pushing or why this would be a problem for WP readers. ---CH 01:05, 21 June 2006 (UTC)

I sincerely hope my comments help, though I have my doubts. If he really thinks his reputation depends on the contents of a Wikipedia article, he's got quite a problem on his hands! I can understand most folks would be upset with public remarks about them that they feel are unfair or inaccurate. His way of responding, however, is not helpful, especially in the context of how Wikipedia works. But as I constantly see played out, anyone can edit, regardless of language skills, subject skills, or social skills. Which mean in order to get the kind of results I want I often have to supply those skills for the other party as well. And if that doesn't work, just walk away. It's a weird environment, but these things happen in the Real World as well.

I've had prior experience here with both Paul August and Jitse Niesen, mathematicians who are now participating in the discussion. They both strike me as intelligent, educated, level-headed, and inclined to try to spread oil on troubled waters. I think they will help get things sorted out. It's just hard for anyone to step into a situation like this and know what's appropriate. That's probably why most people stay away from a brawl; why go looking for trouble?

Certainly I hesitated. But I saw you keep trying to work with Haisch and get bullying and threats in return, so I thought I'd try a few words. I liked throwing in the part about Einstein being from Proxima Centauri, to emphasize the wobbly foundation of Wikipedia credibility. I also tried to help him identify his experience with yours and mine, to support a shift to a less adversarial stance. Unfortunately, my experience suggests that bullies don't respond well to being placated, since that tells them they're winning. That's one reason I began with a no-nonsense "cut out the 'Christine' crap" and continued with other pointed remarks.

Well, we shall see. He has not responded on the talk page since, so perhaps he is taking a time out from that article, per suggestion. On the other hand, in his message to ObsidianOrder he again refers to you as "Christine", despite my admonition and despite a message on his talk page from Paul August. That makes me inclined to write him off as a bad cause. --KSmrq^T 02:39, 21 June 2006 (UTC)

[edit] Blanking responses on Mathematics ref. desk

I noticed you blanked out my response to "Proof?" on the mathemtics ref. desk. That seems very rude to me - how would feel if someone went around blanking out your responses ? A much better approach would have been to put your concerns on my talk page, and ask me if I would consider re-writing my response. I understand all about "do your own homework", but notice that my response does not give the questioner a full solution, because it does not give him the simpler equation that results from making the two substitutions - he has to work this out for himself. Gandalf61 15:50, 7 July 2006 (UTC)

I noticed that too. First of all, KSmrq commented out your reply, he did not delete it. So he's not making it impossible for the interested user to read your solution, rather just delaying that event. I think that perhaps this mitigates the rudeness factor. I note that KSmrq has spent time telling answer-people not to post solutions, and telling question-people how to ask smart questions. He also tends to give long thoughtful educational replies to elementary level questions of the kind that I can't be bothered to answer. In fact, I look forward to reading KS's replies, even when I already know the answer. The point is, I think his refactorings make the help desk a better place, and he should be allowed some leeway. As for whether your reply was too close to a complete solution or not, I have no opinion myself, but I agree with KS's intentions in general. -lethe ^{talk +} 16:11, 7 July 2006 (UTC)

(Reply on Gandalf61 talk page.) --KSmrq^T 21:22, 7 July 2006 (UTC)

[edit] Preview your edits at "order (group theory)"

One of your recent edits at order (group theory) changed "<a>" to "〈a〉" and some similar changes. Was that your intention? JRSpriggs 03:33, 10 July 2006 (UTC)

Yes, I changed greater-than and less-than to left and right angle brackets, as suggested by my edit summary. I also introduced S₃ for use as a running example. As I recall, notation cleanup and examples were the essence of my edit. I did fix a minor mistake (the identity is its own inverse but does not have order 2), but otherwise left the content relatively unchanged, for good or ill. Oh, and looking at the difference report, I see that I also removed a merge proposal tag that seemed ill-considered and had been thoroughly ignored for six months.

Do the characters &lang; and &rang; display badly for you? They're standard HTML 4.01 named entities, and I've used them in other articles without a complaint. These are the preferred characters for this situation. Here's what the HTML spec says:

<!ENTITY lang     CDATA "&#9001;" -- left-pointing angle bracket = bra,
                                     U+2329 ISOtech -->
<!-- lang is NOT the same character as U+003C 'less than' 
     or U+2039 'single left-pointing angle quotation mark' -->
<!ENTITY rang     CDATA "&#9002;" -- right-pointing angle bracket = ket,
                                     U+232A ISOtech -->
<!-- rang is NOT the same character as U+003E 'greater than' 
     or U+203A 'single right-pointing angle quotation mark' -->

This particular spec was last amended in 1999 so even an older browser should understand these (though they did not appear in the HTML 3.2 spec from 1997). Font support, however, is another issue. For example, they are not included in Arial, but are in Arial Unicode MS. The best way I've found to fill missing characters is the freely downloadable Code 2000 font. It makes my page of mathematical characters look pretty. If you're looking at mathematics pages at Wikipedia or elsewhere on the web, you'll probably want to have such a font, especially the release from the STIX font project, available later this year. I'd also highly recommend a browser like Mozilla Firefox that includes native MathML support, to take advantage of BlahTeX. (Be sure to visit their fonts page to get everything you need.)

Or is there some other issue? --KSmrq^T 07:25, 10 July 2006 (UTC)

After I logged off last night, I realized that this was another of those font issues (as you suggest). It did not occur to me at first because I usually only experience those in Internet Explorer and I was using Firefox. To me the quoted characters look like "?a?" (with question marks) in Firefox. While in Internet Explorer, I see square boxes instead of question marks. JRSpriggs 03:03, 11 July 2006 (UTC)

I looked at the Code 2000 page. The sample Latin text was clear to me. So it implies that I have that font already (in Firefox at least). By the way, it has been several minutes and your user talk page has still not finished down loading (I am using a modem over a normal telephone line). Perhaps you could archive some of the images on your page to allow the remainder to be downloaded more quickly. JRSpriggs 03:12, 11 July 2006 (UTC)

I'll see what I can do about archiving or refactoring to improve download times. The servers have seemed slow lately as well. --KSmrq^T 07:04, 11 July 2006 (UTC)

I installed the MathML fonts for Firefox which you recommended, but that string still looks like "?a?" to me. JRSpriggs 03:31, 11 July 2006 (UTC)

I have no idea what the point of the Lorem text is supposed to be: its display has nothing to do with whether you have Code2000 installed or not! For example, I changed the markup to ask for a non-existent font and it still displayed fine. As I suggested before, look at my page of mathematical characters for a reliable indication of what characters you have covered with whatever fonts you have installed.

As for the fonts you just installed for MathML, they will give you pretty results for MathML. However, my recollection is that the part of the software that knows about clever ways to find and display characters in MathML markup is not shared by the rest of the browser. For example, MathML markup might display a fraktur character for a Lie algebra name, but the same entity name or numeric entity might give a missing character elsewhere. A good place to experiment is the BlahTeX online page. --KSmrq^T 07:04, 11 July 2006 (UTC)

Since I have still got no idea how to get my Firefox (let alone Internet Explorer) to render & lang; and & rang; correctly, I have taken the liberty of converting the offending text to < math > using \langle and \rangle which work fine for me. JRSpriggs 02:06, 24 July 2006 (UTC)

[edit] WP:RD/M

Please don't "refute silly claims" by removing others' comments wholesale. Thanks. — Lomn | Talk 21:52, 20 July 2006 (UTC)

I have made no edits to the Miscellaneous Reference Desk. Did you use the wrong link, meaning to refer to the Mathematics Reference Desk (WP:RD/Math)? That's the only one I've had anything to do with lately, but I did not remove any comments there either. I'm guessing there was another server glitch. Checking my contributions I see a bizarre diff attributed to me, but none of those deleted comments were there when I made my tiny addition, and I did not override an edit conflict. I've been seeing this kind of nonsense happen more often lately, which makes me suspect there's a synchronization bug in the database code. Thanks for bringing this to my attention; unfortunately it's a problem for the developers, and typically such bugs are difficult to find and fix. --KSmrq^T 18:01, 21 July 2006 (UTC)

You have on a few previous occasions deleted comments by me during simultaneous edits. I wonder if for some reason MediaWiki isn't informing your system about edit conflicts. -lethe ^{talk +} 18:27, 21 July 2006 (UTC)

I wonder. My practice any time I see an edit conflict is to save my text (externally), back out of the edit completely, refresh the page (with a forced reload), and then edit anew with my saved text. I don't know how to be any safer or more precise about the location of my edits than that. If the software and servers are working correctly, this should be equivalent to never having an edit conflict. In this instance I went through just such a process, and never saw the text that went missing. That suggests a bug such that the left hand does not know what the right hand is doing. Somewhere it knows about the text that goes missing, because it shows up in the change log; but it does not show it to me or flag an edit conflict for my renewed edit.

Perhaps the forced reload is inadequate; my browser is not using its cached page, but maybe the server is using cached data. But there would need to be a bug in the method of catching edit conflicts, so that the deletion could occur without raising a flag. Or perhaps the notification mechanism has a glitch where thinks it has already given notice once, and so now is allowing me to override the notice with no comment. And all of these possible bugs assume the problem relates to my refresh/re-edit behavior. But we've seen such problems more widely, and I doubt that my practice is followed by others.

Bugs that depend on a sequence of interleaving independent events are some of the most difficult to identify, reproduce, isolate, and fix. In a large body of code maintained by multiple programmers, it's worse still. --KSmrq^T 19:19, 21 July 2006 (UTC)

[edit] Congratulations!

You now have your very own sidebar at the bottom of www.wikipedia-watch.org/hive2.html

At this rate, you'll find yourself on ArbCom in no time at all. 68.89.131.18 20:30, 24 July 2006 (UTC)

[edit] You're famous

Bernard Haisch has quoted you in the LA Times [4]. Paul August ☎ 23:38, 24 July 2006 (UTC)

Lucky me. Since I haven't registered at the LA Times (and probably won't), I suppose I'll have to miss my moment of fame. But I seem to be quoted (out of context) elsewhere on the web as well. Apparently someone (me) who is critical of Wikipedia's content control is considered to be a "Wikifascist". An original perspective. Also ironic is that my remark to Haisch was in a thread about a dispute with Chris Hillmann, whose views on the credibility of Wikipedia may not be all that different from those of Wikipedia Watch. For future reference, here are my remarks in toto, with a (late) reply by Haisch:

---

It seems to me, Haisch, a deliberate insult to CH to continue to refer to him by the wrong name, "Christine". I have watched enough of your behavior to think he is absolutely right to suggest you need a time out. You do not get to choose whether or not an article on you appears in Wikipedia, and you have no veto power over its contents. The article can cast you as a genius or an imbecile, a respected scientist or a crackpot. Experience shows excesses tend to dampen over time, converging to something factual and NPOV. If your reputation depends on what Wikipedia says about you, it is a very fragile reputation indeed. The fact is that at any given instant a vandal could replace a page, any page, with total gibberish. The page on Einstein might have a statement inserted to the effect that he was a Nazi collaborator, or that his theories have been totally discredited, or that he was a silicon-based lifeform from Proxima Centauri. Wikipedia is what it is, and to treat it as if it were, say, a peer-reviewed journal will only doom you to endless frustration. Wikipedia does not operate by your rules, but by its own conventions; I suggest you learn to accept it. I have been exasperated on occasion, as has CH, as has any thinking person who has been involved here for long. The fact that anyone would treat the contents of Wikipedia with respect is an indication that somehow, miraculously, its crazy non-academic methods produce unexpectedly viable results. I don't claim to understand it myself, but I can assure you resistance is futile. In my view, not only CH, but also other editors, have been doing a fine and generous job within Wikipedia conventions to accommodate you. You may never be satisfied with the result. Ah well. Outside of Wikipedia the same thing is true: you don't get to impose on people what opinion to have of you, nor with what respect to treat your work. As in life, so in Wikipedia. Your only power here is the power of persuasion. Please feel free to continue to use this talk page, but you may be surprised to find what a week away from the struggle can do for your equanimity, and your effectiveness. --KSmrq^T 20:08, 19 June 2006 (UTC)

My goodness Mr. KSmrq, you certainly seem to be intoxicated by the power of the faceless, nameless proletariat. You have done an excellent job of articulating the danger of mob rule, though I don't think that was your intent.

Haisch 06:18, 22 June 2006 (UTC)

---

He apparently interprets my remarks as saying vandalism is a good thing, rather a bizarre spin. When I said, "If your reputation depends on what Wikipedia says about you, it is a very fragile reputation indeed", did he hear me? I doubt to this day that he sees himself as part of the problem, not part of the solution. And I note that Wikipedia Watch also elides my statements that do not suit their spin. At least they kept my favorite part, about the "silicon-based lifeform from Proxima Centauri." :-D

I wonder what they think of "government of the people, by the people, for the people". I'm assuming Lincoln was referring to the "faceless, nameless proletariat", as Haisch puts it. It's an interesting comparison, because the U.S. constitution buffers the goverment from the people in several ways. Legislation is enacted by representatives, not plebiscite. Senators were originally chosen by state legislatures, not by general elections. To this day the President is formally chosen by an Electoral college. And the tiny, unelected Supreme Court can override the other two branches of government if they do not respect the constitution. Yet the "mob" is allowed to vote.

Anyway, casting the editors of Wikipedia as a proletariat mob seems a perversion of Marxist theory. Are we to believe that CH is both working-class and part of a mob because he joins mainstream science in opposing some of the theories Haisch is pushing? I don't think so. --KSmrq^T 14:08, 25 July 2006 (UTC)

You should submit this response to the LATimes, if such a thing is possible. Their readers deserve to know what a skewed one-sided presentation they were given by an author incapable of understanding even simple points. Well, I don't know if the LATimes wants to become the venue for an internet flamewar, but still... -lethe ^{talk +} 15:50, 25 July 2006 (UTC)

(Laughing) Ironically, as KSmrq guessed might be the case, except for his omission of the context for my creation of Bernard Haisch and his mischaracterization of my motives, I seem to largely agree with his main points. See User:Hillman/Media commentary on Wikipedia. The New Yorker piece by Schiff is a particularly interesting addition to the genre of media profiles of the State of the Wikipedia.---CH 12:36, 26 July 2006 (UTC)

I presume from you remarks, that the above link doesn't work for you. It still works for me, and I don't have a subscription either. Try [5], then under the news menu on the left select "Opinion", and you should find a link to the article Why Wiki Can Drive You Wacky", under the column labeled "OP-ED".

Here's an excerpt from the Haisch piece:

"YOU DO NOT get to choose whether or not an article on you appears in Wikipedia, and you have no veto power over its contents. The article can cast you as a genius or an imbecile, a respected scientist or a crackpot…. a vandal could replace a page, any page, with total gibberish. The page on Einstein might have a statement inserted to the effect that he was a Nazi collaborator, or that his theories have been totally discredited, or that he was a silicon-based life form from Proxima Centauri…. Wikipedia does not operate by your rules but by its own conventions; I suggest you learn to accept it…. I can assure you resistance is futile."

This was the lecture I received from anonymous Wikipedia "editor" KSmrq while I was in the midst of trying to bring some semblance of accuracy and neutrality to the "Bernard Haisch" article that another "editor" had posted a few days previously. I put "editor" in quotes because anyone can be a self-appointed editor. KSmrq's user page says: "Although I do have personal history, interests, education and professional experience, I feel no compulsion to share them with the world on this page." Now that inspires trust and confidence!

Paul August ☎ 18:35, 25 July 2006 (UTC)

That worked; I was able to read the article. Thanks! (I think.)

How much confidence should I have in someone who includes my remark about privacy, but neglects to quote the very next line?

"My intent in contributing to Wikipedia is that the quality of my edits speaks for itself. Accuracy, appeal, readability, and NPOV are always my aims."

Where I ask to be judged by my actions, not my external credentials, Haisch wants to intimidate us with his credentials to spin our view of his poor actions. Demosthenes had something to say about that in the third of his Olynthiacs:

"I must ask you to bear with me if I speak frankly, considering only whether I am speaking the truth, and speaking with the object that things may go better in the future…

"It is impossible, I say, to have a high and noble spirit, while you are engaged in petty and mean employments: whatever be the pursuits of men, their characters must be similar."

Haisch claims to have been seeking "accuracy and neutrality", yet also said here he felt it was important that Wikipedia show him and his work in a positive light to help him secure funding. How ironic that he attacks the reputation of an anonymous Wikipedian in the op-ed section of the LA Times by omitting relevant information, while protesting omissions of his record. I still find it hard to imagine a serious (scientific) funding source that bases its decision on the contents of Wikipedia. --KSmrq^T 20:27, 25 July 2006 (UTC)

You're welcome. As recent events have shown It is difficult for any of us to remain coolly dispassionate when it comes to our reputation. I'm just glad I don't have an WP article about me. In fairness to Haisch, I suspect he would say that, rather than wanting his WP article to paint a favorable picture, he simply did not want it to paint an unfavorable one. Paul August ☎ 22:04, 25 July 2006 (UTC)

That reminds me: Did you notice I changed the title of this section? Yep, I changed it from "Yor're famous" to "You're famous". I hope you don't mind. ;-)

I can understand that it's natural for us to care how we're seen; for a time, ancient Athenians formalized a curious practice called ostracism, an election nobody wanted to win! Which makes it sad that someone like Haisch would not accord others the respect he wants for himself. --KSmrq^T 23:59, 25 July 2006 (UTC)

Yup. Paul August ☎ 03:40, 26 July 2006 (UTC) P.S. Please don't change the words that I wrote! People will naturally assume, incorrectly, that I can type and spell ;-)

Hi, KSmrq, you might be interested in this MfD. See in particular this section of my essay on User:Hillman/Digging. ---CH 00:57, 29 July 2006 (UTC)

[edit] Quote

Hi, this article contains your "Proxima Centauri"-quote. I like it, aldo I would have used a more diplomatic way of saying the same. Have you objection if I use that quote for the quote section of Wikizine? And can you provide a link to the original page where you have written that to make sure the quote is correct? Greetings, --Walter 09:47, 31 July 2006 (UTC) (I preffered not to post this in public but your email function is disabled)

Thanks for asking. Indulge me in a linguistic nicety:

Usage Note: People have been using the noun quote as a truncation of quotation for over 100 years, and its use in less formal contexts is widespread today. Language critics have objected to this usage, however, as unduly journalistic or breezy. As such, it is best avoided in more formal situations. The Usage Panel, at least, shows more tolerance for the word as the informality of the situation increases. Thus, only 38 percent of Panelists accept the example He began the chapter with a quote from the Bible, but the percentage rises to 53 when the source of the quotation is less serious: He lightened up his talk by throwing in quotes from Marx Brothers movies. — The American Heritage Dictionary of the English Language, 4/e

As for the accuracy of the quotation itself, I have reproduced it in full just above; and you can confirm its provenance from this edit history of Talk:Bernard Haisch. Closer scrutiny shows that I added the "Proxima Centauri" part as an afterthought, for emphasis.

It appears that Haisch has had published in the LA Times op-ed section what, on cursory glance, appears to be the same letter. The exact same excerpt from what I wrote may be found elsewhere on the web, where I am characterized as a "wikifascist".

As you may now suspect, I would object to subverting Wikizine to publicize Haisch and his campaign of distortion. Thoughtful Wikipedians will discover the bigger picture for themselves; it's not hard to do. Let Haisch be "hoist with his own petard". --KSmrq^T 19:41, 31 July 2006 (UTC)

[edit] Wikifascist

I think that the word Wikifascist has been thrown around enough to warrent its own wikipedia article to explain what the term means? Is it Quixotry to try? Perhaps...can you help me write the article so it will stick? In Defense of the Artist 23:20, 3 January 2007 (UTC)

[edit] Loved your Greetings

i loved your greetings page. Wonderful. Also thanks for the illumination about TeX issue on the Mobius Transformation talk page. Wow... you have beautiful wallpaper images here... Xah Lee 02:33, 1 August 2006 (UTC)

[edit] Reversion

Please do not revert edits to User talk:Hillman which are in violation of WP:STALK. TIA. DrL 15:47, 2 August 2006 (UTC)

Don't try to cloak yourself in Wikipedia conventions. I have now read the dialogs between you (and your "advocate") and CH, and you are clearly violating the agreement. To wait until someone announces they are taking a break and then go change what they have written on their user talk page is obnoxious behavior. Furthermore, if your interest is anonymity then it's rather stupid to instigate a public fight, which only serves to draw more attention to a previously obscure Dig page and the question of your identity. I see no evidence that CH is trying to harass or intimidate you, but overwhelming evidence that you are so attacking CH. I do not know if you are "a short, garrulous woman with a heavy Brooklyn accent" or "an invisible six-foot three-and-a-half-inch tall púca". You could be Gina Lollobrigida or Gina LowEyeQueue. I don't much care. What I do care about is your misbehavior connected with Wikipedia. These elisions are just the latest example. I do wonder, are you really trying to protect an identity, or to advertise it?

Given that the decision just reached in the MfD case is keep, it appears that the Wikipedia community does not consider CH to be stalking you. So please, leave his pages alone. TIA, and TTFN. --KSmrq^T 17:18, 2 August 2006 (UTC)

• Please do not rv the page again. The MfD closer himself stated that the personal information in those pages is being redacted. Please read his statement. You are reverting to edits in violation of WP:STALK. Please desist. TIA. DrL 17:35, 2 August 2006 (UTC)

We seem to disagree. Your repeated assertions of stalking do not make it so, and are supported by neither the facts nor the MfD decision. You're not helping yourself here. HAND. --KSmrq^T 18:04, 2 August 2006 (UTC)

Thanks for your feedback. I do appreciate your tolerance. I will try to be a better Wikipedian as well. HAND. DrL 19:59, 2 August 2006 (UTC)

Hmm, dropped by to thank you for your reversion of DrL's "redaction", as she calls it (I'd say "potential destruction of evidence", particularly since these messages speak to my motivation for the disclosures which have led here to call for my permabanning in various places as recently as 10:43, 1 August 2006 message; see also this message posted to Wikipedia:Administrators' noticeboard/Incidents, sheesh. My position is that she seems to be threatening to put me in a position in which I might need to defend my own actions. I am trying to clarify this with her AMA rep, User:David.Mestel, and I am requesting protection of my talk page archives to guard against more alterations like this. Anyway, thanks much. ---CH 22:13, 10 August 2006 (UTC)

You sure pick your fights. :-)

I'm not much impressed by bluster and intimidation, and I suspect it will get a chilly reception in the collegial culture of Wikipedia. The campaign against you reminds me of mob and Scientology tactics, more recently popularized by the Bush 43 administration, the "agree with us or we break your knees" brand of persuasion.

Wikipedians would do well to learn to firmly oppose threats, insults, and other incivility; to insist that everyone play nice or play elsewhere. Behavior like that of DrL must be quickly and unequivocally squelched.

Then, of course, we need to get our facts straight. --KSmrq^T 22:40, 10 August 2006 (UTC)

Did you notice that in this edit, Asmodeus by implication wishes to demote his critics to subhuman status? Except of course for me; he maintains that I am merely a nonhuman ;-/ ---CH 22:40, 14 August 2006 (UTC)

I read the statement on your user page, "Some say I am a software agent which believes it is human." Since you have behaved so rationally in the face of provocation that would drive a mere human non-linear, I naturally assumed the best, that you are nonhuman! Of course, it's no use your denying it; that merely confirms the belief part. ;-)

Dehumanizing opponents is standard operating procedure in human conflicts. The "good guys" (us) do it; the "bad guys" (them) do it. Which raises the question: Who's talking to what at the peace table? Skilled negotiator Richard Holbrooke quotes Yitzhak Rabin as saying, "You don't negotiate with your friends, but you do negotiate with your enemies." However, he also says, "Bin Laden you can't negotiate with. … [I]t's clear from what he did and what he said that his only goal is to destroy, destroy, kill, kill."

Four books I have found worthwhile reading are

1. Robert Axelrod. The Evolution of Cooperation. (ISBN 978-0-465-02121-5)
2. Roger Fisher, William Ury, Bruce Patton. Getting to Yes: Negotiating Agreement Without Giving In, 2/e. (ISBN 978-0-14-015735-2)
3. Robert Cialdini. Influence: Science and Practice, 4/e. (ISBN 978-0-321-18895-3)
4. Everett M. Rogers. Diffusion of Innovations, 5/e. (ISBN 978-0-7432-2209-9)

The common theme here is social psychology. Why is it that a graduate student is taught the technical essentials to succeed, but not the communication and social essentials? These books provide some fascinating and relevant science. --KSmrq^T 00:37, 15 August 2006 (UTC)

[edit] A polite request for KSmrq

Hello, KSmrq. Lest there be any confusion, my point in allowing David Mestel to speak on my behalf on User Hillman's Talk page is to resolve a problem, not to spectate with my hands tied while people with "outside perspectives" and wheelbarrows full of POV commandeer the discussion, wail about unauthorized tampering with Hillman's bizarre and invasive dig pages, and paint the sky with praise for its putative expertise in General Relativity (which is irrelevant to the matter under discussion, and as far as I can tell, no big deal at that).

I suggest that if you want User Hillman to stop "crank fighting" and write Wikipedia articles, then you should be discouraging its shrill and clumsy attempts at the former, and encouraging it to spend more time on the latter. In fact, this probably applies to you as well. In any case, what is now transpiring on Hillman's talk page is not another AfD or DR to which hostile participants have been lured by deception; it is a negotiation which does not involve you, and does not require your input. (I'll be sure to let you know if it does.) Thanks, Asmodeus 00:31, 14 August 2006 (UTC)

Your request is anything but polite. Your comments here, as almost everywhere, are abusive. Please read and abide by WP:CIVIL and WP:NPA. The negotiation does involve me; DrL saw to that by reverting me. Even absent that, I am part of the Wikipedia community; it is up to me, not you, to decide what involves me. --KSmrq^T 00:58, 14 August 2006 (UTC)

[edit] re Your Message

He only suggested it to me, his advocate, in discussions that were not intended for public consumption. --David Mestel^(Talk) 06:39, 18 August 2006 (UTC)

Welcome to the world of Wikipedia, where everything is public. Perhaps you can appreciate the quandary of CH with more sympathy. That aside, what I said is something you and DrL and Asmodeus all need to absorb. This is neither a social club nor a court of law. This is a very public international community trying to create an encyclopedia. Surely you do not object to me encouraging DrL to fully support the negotiation. And based on your discussions with CH — which everyone can see — I don't think you yourself adequately came to grips with the pivotal importance of the assurance requested. Furthermore, you wrote as if you could speak for Wikipedia in saying how policies should be interpreted and applied, which is false, and does not serve the negotiation. You can represent DrL and Asmodeus and yourself; you certainly do not speak for all the editors who chose to keep the Dig pages. (And I point out again that I abstained from that decision for reasons I have previously stated.) Please try to model for DrL and Asmodeus the ideal behavior of a Wikipedia editor — which does not include bluster and statements unsupported by the facts.

It was helpful to try to explain the motivations of those you represent, as CH asked. It was not helpful to ignore the request for assurance, which is essential for CH's needs. In a successful negotiation everyone must succeed. Both sides must feel they are better off with the agreement than without. Without a commitment by those you represent that they will abide by the agreement, all negotiation is a sham. Already CH has offered that assurance on his side. Now it is your turn.

I see that you will be away for a vacation. Perhaps it would be wise to ask a colleague to fill in for you while you are away; or perhaps it would be even better if everyone took a break from this matter. As you think best. Either way, enjoy your break. --KSmrq^T 13:09, 18 August 2006 (UTC)

[edit] Reversion of the day

Uh, should I assume you're working on a response? Or are you away from the computer? It's been a while... Melchoir 23:19, 23 August 2006 (UTC)

Response posted. It took awhile, as I dug out some books and typed in some excerpts with "penalty type" (as mathematics notation came to be known among typesetters) on the talk page. I'm winding down for the day, so if you have any urgent thoughts, get 'em in quick. --KSmrq^T 00:42, 24 August 2006 (UTC)

[edit] ISBNs

I was looking at something like this User:Rich Farmbrough/ISBN template as the next stage. Thus (almost) all ISBN's would change at the right second, and the template could be substed out later. The test template works but doesn't support hyphens. So a new template is required which is actually easy to code, I'll do it later today or tomorrow. Rich Farmbrough 10:05 29 August 2006 (GMT).

More thought to the timing would be good, because we throw away checksums, the ones we generate are valueless from a checking POV. I have more to say, but not the time to say it just now. Thanks for your comments. Rich Farmbrough 10:05 29 August 2006 (GMT).

Wikipedia:AutoWikiBrowser/Settings - they are auto generated from the table, and hence are a little long winded. Rich Farmbrough, 20:46 7 September 2006 (GMT).

[edit] A London Life

Hi KSmrq, how did you figure out the hyphenation pattern to use with this ISBN? When I look them up at Amazon or Library of Congress, they are usually shown without hyphens. I notice that the length of the second field isn't always the same. EdJohnston 14:44, 2 September 2006 (UTC)

I assume you're referring to the first of these:

• Henry James: The Middle Years 1882-1895 by Leon Edel (New York: J.B. Lippincott Company 1962) ISBN 0-380-39669-6
• The Portable Edmund Wilson edited by Lewis Dabney (New York: Penguin Books 1983) ISBN 0-14-015098-6
• The Tales of Henry James by Edward Wagenknecht (New York: Frederick Ungar Publishing Co. 1984) ISBN 0-8044-2957-X
• A Henry James Encyclopedia by Robert L. Gale (New York: Greenwood Press 1989) ISBN 0-313-25846-5

If you want to work it out for yourself, you can follow the rules here at isbn.org. Far easier is to use this online tool at the same site, which not only hyphenates 10-digit ISBNs, but converts them to 13-digit ISBNs (also hyphenated) at the same time. Frankly, I'm not convinced that hyphenation adds value; in fact, it may even be a liability in web searches.

The fact that the proper hyphenation depends on the number is a nuisance. For example,

99921-58-10-7

9971-5-0210-0

960-87363-3-1

80-86119-13-0

4-8457-0667-9

0-14-015098-6

0-446-60098-9

0-8044-2957-X

0-85386-070-X

0-901690-54-6

0-9500000-0-0

are all correct. Worse still, the proper hyphenation is not determined by a centralized international authority, and requires consulting ever-changing tables like this one. --KSmrq^T 18:14, 2 September 2006 (UTC)

[edit] 4RR

Please note that you have reverted Proof that 0.999... equals 1 four times in the last 24 hours: [6] [7] [8] [9] Please undo this last revert, or you may be blocked in accordance with Wikipedia:Three-revert rule. In the future, I advise you to refrain from using popups to conduct edit wars, as they are especially disrespectful; see Wikipedia:Revert#Rollbacks. In the case of this particular article, I ask you to please respect the emerging consensus on the talk page, and for everyone's good, undo this edit. Melchoir 05:18, 6 September 2006 (UTC)

Again you are absurd. You have made a huge number of changes pushing your agenda in the same time period, compared to my three, not four. (Reverting The Anome's move—your third cited instance—does not count.) --KSmrq^T 07:03, 6 September 2006 (UTC)

I am unhappy that I edged up to the 3RR line, but I am sure that I did not cross it. Arthur Rubin seemed to think that a reversed page move counted towards his own 3RR counter, and he's an admin. Despite my dismay at his initial actions yesterday, I have found him to be refreshingly reasonable after a bit of discussion; you might want to consider that emulating his restraint and willingness to engage would win you more supporters than your present MO, not to mention lowering your own stress level. In any case, I'm not your mother. I've given you the same warning I would have given anyone else; now I have reported you at Wikipedia:Administrators' noticeboard/3RR. Melchoir 16:28, 6 September 2006 (UTC)

Actually, I find that my stress level is considerably reduced. I've "engaged" with you repeatedly in the past, at length; it was a total waste of time. I have made it quite clear that I do not intend to continue to waste words on you. --KSmrq^T 18:55, 6 September 2006 (UTC)

I am not the only editor involved here, nor even the only editor you have recently reverted. If you are unwilling to consider my sincere advice, I can only hope that other community members will change your mind. Melchoir 19:36, 6 September 2006 (UTC)

I do wish you two would work it out. When one (or both) parties to a dispute is obviously (an) idiot(s), quite frankly I prefer to see the dispute escalate so that the guilty party(ies) can be banned as soon as possible, and out of our hair. But in your cases, I've worked productively with both of you in the past. Also, from a cursory reading, the two versions of the article in question both seem acceptable, so it's hard to imagine that a compromise can't be found. --Trovatore 19:41, 6 September 2006 (UTC)

Thanks for stopping by; I appreciate your good wishes for a happy resolution. Unfortunately, been there, tried that; didn't work.

In the past I wrote at length on the article talk page, and also on Melchoir's own. To no avail. I call your attention to Talk:Proof that 0.999... equals 1/Archive08#Geometric series proof. Early on I pointed out four easily corrected problems, with documentation; no response. In one post I made a detailed list of six mistakes; the response was a complaint that the list was too long, so would be ignored! Then he came up with the WP:NOR assault, at which point I threw up my hands in disgust and asked other editors to deal with him (which they tried to do, with limited success). Now he rewrites the whole article with visions of grandeur, ignoring the concerns I have (repeatedly) raised.

Unfortunately, the history of debate has recently been buried in the archives, and it takes more than a cursory glance at the article versions to appreciate the damage Melchoir has inflicted.

It could be a nice little service article, but it is not a productive use of my limited Wikipedia time to "debate" with Melchoir. He is gaming the system, and I'm not going to play (again). --KSmrq^T 20:38, 6 September 2006 (UTC)

While I do not accept your narrative, it is irrelevant to the present question. After reading it, I still do not understand your objection to the article, nor do I see a path towards compromise, improvement, reconciliation, or any positive future outcome. I am putting a huge amount of effort into remaining optimistic about you, and you've got to help me out by letting go of the past. We're all sick of hearing it. Melchoir 20:54, 6 September 2006 (UTC)

I have to admit that I am wary of the word "compromise" because I honestly do not understand what purposes are better served by KSmrq's version than by mine. Can someone fill me in? Melchoir 20:01, 6 September 2006 (UTC)

[edit] Do you want to add your advice to the Math Manual of Style?

Hello KSmrq,

At [10] you proposed a reference style for math articles. See also your previous entry on the same Talk page about citation templates. This advice ought to be saved somewhere. I proposed adding it to [11] to which there is a link on the project page at WP:WPM. Does this task interest you? I would consider doing this myself but didn't get any response to my suggestion of moving the stuff there. EdJohnston 16:48, 9 September 2006 (UTC)

[edit] 0.999...

Listen KSmrq, you are alone or nearly alone in this situation, and you must not continue to revert to a version from a long time ago with NO explanation. Doing so is considered vandalism, and you can be blocked for it. Consider this your last warning. —Mets501 (talk) 00:48, 15 September 2006 (UTC)

No explanation?!! I've explained until I'm exhausted. Also, the fact that Melchoir has the time and obsession to make a non-stop stream of edits during a day does not change the fact that his changes are all very recent. I happen to have a real life that needs more attention than yet another fruitless argument. In fact, I have had little time for any of Wikipedia in recent weeks. If an edit summary will placate you, I'll add one; but it will say nothing new. Furthermore, we know from past history that other experienced editors also vehemently object to Melchoir's edits. It is entirely inappropriate for you to accuse me of vandalism and threaten me with a block when you have sided with Melchoir in these debates.

Just above this conversion we see a threat from Melchoir to have me blocked for violating 3RR, which was a demonstrably false accusation, trivially. And this when he was making massive numbers of edits. Now you threaten to block me for vandalism, which the history also refutes. This is bullshit. There are plenty of experienced mathematicians/admins around who know me and my values and my edits. I suggest that if you want a high quality, stable article that you direct your attention to putting the brakes on Melchoir, and that you engage me in dialog rather than threats.

I have expressed my appreciation for your efforts in previous discussions, and would be willing (as time permits) to try talking with you further about the current situation. --KSmrq^T 01:41, 15 September 2006 (UTC)

Part of any wiki is the fact that editors can change articles; it's actually a policy, as I'm sure you know, to be bold. Have you taken part of discussion recently to try and find a solution between you and Melchoir, instead of just saying that his version sucks? That is all I seem to hear from you. All you do is whole-scale reverts to a much earlier version, which consensus is against on the talk page. Have you even taken a look at the talk page? Do you find more people who agree with you or more who agree with Melchoir? It's called consensus, and it's also a policy on Wikipedia, that must be followed. You clearly don't have consensus for your large scale reverts, so therefore they cannot be done, and quite the opposite is true for Melchoir (there seems to be a decent consensus on the talk page preferring his version). I propose you think this over, and try not to perform whole-scale reverts again. —Mets501 (talk) 10:57, 15 September 2006 (UTC)

If this is your idea of dialog, of asking my views, forget I offered. I have been contributing to Wikipedia roughly twice as long as you, and have both created and collaborated on substantial articles, so condescension like "It's called consensus" is inexcusably insulting. You have quite a lot to learn about the difference between a consensus and a cabal, and about how Wikipedia really works.

If you change your mind and want to find out in more detail why I object so strongly to the rewrite, stop by again. But if you really think fifty or a hundred footnotes are a substitute for good writing, we probably have nothing to discuss anyway. --KSmrq^T 11:58, 15 September 2006 (UTC)

I really have trouble understanding this dispute. I've looked at both versions and, while I haven't gone over either of them the way a journal referee would, both appear to be substantively correct. There are piles of verbiage in the talk archives, which I'm not interested enough to wade through. Could I ask that each "side" give a brief executive summary -- say, two sentences or a brief paragraph -- of what their case is? --Trovatore 15:15, 15 September 2006 (UTC)

Sure. This is an encyclopedia article: a verified overview of every published approach to the subject, with enough details on all levels that every reader will learn something from it, and which answers nearly every question which has arisen on the Talk Page for the last year; it adheres to all of our policies; with a little more historical background and cleanup of connecting prose it will be Featured quality and something all Wikipedians will be proud to display on their Main Page. This is an unreferenced collection of opinion, speculation, and original research that has been stunted to the point of POV by omission, relegating critical concepts to a See also section because they don't jive with How The Author Would Like You To Do Mathematics; if you nominated this Start-class article for as much as GA you'd be denied in record time. Melchoir 16:39, 15 September 2006 (UTC)

Maybe I wasn't clear in my request. I don't want to go reread the articles in detail. I'd like you each to give the one or two most important specific particulars in which you feel your article is better. --Trovatore 17:33, 15 September 2006 (UTC)

Factual or not; comprehensively neutral or not. Melchoir 17:47, 15 September 2006 (UTC)

With examples, please. --Trovatore 17:50, 15 September 2006 (UTC)

Factual:

• "Elementary proofs" and "Advanced proofs", which is POV; replaced by "Digit manipulation", "Real analysis", and "Rational constrcutions", which is informative.
• "It should be no surprise that a notation allows a single number to be written in different ways" replaced with "Decimals are not the only notation in which a single number can be written in different ways. ... Students are often 'mentally committed to the notion that a number can be represented in one and only one way by a decimal.' ", with citation.
• "through each decimal place in turn, induction shows": use of induction is unsupported and unexplained; replaced by a simpler method, with citations.
• "non-Archimedean; but it is difficult to discuss decimal expansions in them": original research and incorrect, refuted with citation.
• "The existence of such alternatives is one reason ... why the advanced proofs require more care than might be supposed.": POV, removed.
• "One reason might be that people encounter it at a time when they are young and curious, and the usual explanations seem unconvincing.": speculation, replaced by actual research, with citations.
• "Another is that, like many such magnets, the statement of the proposition is elementary, but the proof is not.": speculation, POV, removed.
• "Professor David Tall has gone so far as to study characteristics of teaching and cognition": POV, removed.

Comprehensive:

• "Real analysis", including series, sequences, and suprema, is new.
• "Other number systems": Non-standard decimals, all of "Breaking subtraction", and virtually all of "p-adic numbers" is new.
• "Applications" is new.
• "Skepticism" is almost entirely new.

Is that enough? Melchoir 18:07, 15 September 2006 (UTC)

KSmrq, your rebuttal/counterclaims? Again, please, executive summary style, the most important two or three points, with examples. --Trovatore 18:21, 15 September 2006 (UTC)

[edit] Please archive your talk page!

It takes much too long to load the images, which discourages some users (like me) from trying to reply to your messages, especially when (as currently appears to be the case) the WP servers are stressed and service is slow! The tiling pictures are lovely, incidently, just not a good idea on your user talk page IMHO.

Thanks for letting me know about User:Paul August, but while I did see the Signpost news items about the Carnildo thing, I have never encountered this admin and don't really understand what this is about. I am not sure how Paul August's protest relates to my concerns about quality control; he seems to be concerned with alleged admin misconduct. (If the edits he quoted were supposed to indict Tony Sidaway, who I have interacted with, I don't see the problem, in fact Sidaway's comment seems mild. Or was the problem that Sidaway blocked the user who made the "defiant" comment? How long was the block for?) ---CH 00:53, 19 September 2006 (UTC)

[edit] Slerp Formula

Why do you constantly change the formula for slerp back to its old form. I have found numerous references and talked to numerous people who all agree that those parentesis are necessary. —The preceding unsigned comment was added by 74.135.173.196 (talk • contribs) 19:35, 2006 September 30.

(Please sign your comments.) Then your sources lack mathematical maturity. Since Ω is an angle, and given the structure of the formula, anyone capable of understanding Slerp in the first place can also understand that the Ω is part of the argument to the sine function. Extra parenthesis are burdensome clutter in this context. The original peer-reviewed paper in which Slerp appeared uses the same form (with different variable names):

If it's good enough for the inventor and the SIGGRAPH reviewers, it should be good enough for Wikipedia. Programming languages require more explicit syntax than we use for written mathematics; few programming languages would allow the two-dimensional fraction notation either. I suggest you learn to be comfortable with the conventions of mathematics; otherwise you will be unable to read the original Slerp paper and most of the surrounding literature.

In future, please discuss issues like this on an article's talk page. --KSmrq^T 20:24, 30 September 2006 (UTC)

[edit] Richard Gabriel / ISBN

First, the 13 digit ISBN doesn't take effect until 2007. Second, you put in a 13 digit number that, when a search is attempted, produces ZERO results. So who is that helping? Certainly not anyone interested in reading Gabriel's poetry. And how is that accurate for an encyclopedia? -- one of your stated editing goals. The 10 digit ISBN, on the other hand, produces any number of results. I'm not going to mess with it because, 1)I'm very new here, 2)somehow when in the previous edit I got the publisher's link to work so at least interested parties can find the book somewhere. But there ought to be a reconsideration of this policy because you are a bit ahead of things with a negative result. Ibar88 21:21, 3 October 2006 (UTC)

Welcome to Wikipedia. I see you're so new here the welcoming committee has not yet found you!

Usually a discussion about edits to an article will be conducted on the article's talk page, so that it is preserved with the article where all interested parties can see and possibly weigh in.

But I can give a short answer about ISBN-13. I'm not sure how you got "ZERO results", but one of the standard sources for items like this is Abebooks, and its search result turns up four copies. That's pretty good for an obscure 48-page book of poetry! This is the first individual bookseller listed on

Special:Booksources

which is where the Wikipedia ISBN link takes you. It's disappointing that Amazon.com does not yet recognize ISBN-13, but in less than three months it will be the standard, and it has long been the number on bar codes. Anyway, in this specific instance we now have both a link to a publisher page and a link for an ISBN search, so I think readers who want to get their hands on Dick's poetry are well served. I should think more readers would be interested in his Stanford band, The Wizards, about which the article says nothing. --KSmrq^T 23:05, 3 October 2006 (UTC)

There's a lot to learn here and I thank you for the welcome. I think the resolution is satisfactory with the publisher link enabled. The book is in print. It was part of a chapbook series of 12 from established poets like Tony Hoagland and less well known poets such as Gabriel. I only know him and of him through the literary aspect of his life so I can' really add anything to the music part. Ibar88 00:00, 4 October 2006 (UTC)

His websight says, "He is the lead guitarist in a rock 'n' roll band and a poet." Obviously he's proud of both, but I notice he lists the band first. He says:

“In 1983, my then-band, The Wizards, played a gig at Jack Alpert's place on Stanford campus. The invitation included a letter purported to have been written by Hunter S. Thompson about an earlier Jack Alpert party my band played at. Despite what you might think about his politics, his morality, or his sanity, Hunter S. Thompson was a fine writer.”

His father had founded a music school and played trumpet under Arthur Fiedler, so perhaps influenced his fondness for music. --KSmrq^T 08:53, 4 October 2006 (UTC)

[edit] Floating point and e

On Talk:Floating point you write:

Some transcendental numbers like e can be represented exactly using continued fractions.

Which I don't quite follow. e can certainly be represented mathematically as a continued fraction. And in a computer, it could be represented symbolically or algorithmically, but not with any finite continued fraction. So I think your point to include e in the discussion is spot on, I think the mention of continued fractions actually makes you point less clear (to me in any case). That said, I really appreciate your thoughts on where we should head and think your comments will help move things in a better direction. Cheers, Jake 00:09, 5 October 2006 (UTC)

The continued fraction for e is

[1,0,1, 1,2,1, 1,4,1, 1,6,1, 1,8,1, … 1,2k,1, …].

(Usually the leading "1,0,1" is regularized to "2", though this blurs the pattern.) Thus a tiny representation can provide the n-th position of its continued fraction on demand. For computer manipulation, this counts as an exact finite representation. Anything we need to compute with e, to any precision, we can. I deliberately chose something that looks very different from a floating point representation. It’s meant to loosen the mind. --KSmrq^T 03:01, 5 October 2006 (UTC)

[edit] Image:Villarceau_circles.gif

One quibble is that I believe it might help if the inside surface of the torus is colored or textured so it is visibly distinct from the outside surface

What do you mean? Isn't green inside and blue outside good enough? :S They look very distinct to me. Also, I DID experiment with a different texture (hexagons, stripes and plain colors), but it looked pretty boring or ambiguous, so I used checkered pattern inside too. ☢ Ҡi∊ff⌇↯ 08:53, 8 October 2006 (UTC)

[edit] CH

I, as every other admin, can assure you that CH himself proposed his user and talk pages for deletion.

• http://en.wikipedia.org/wiki/Special:Undelete/User_talk:Hillman

Pjacobi 07:12, 12 October 2006 (UTC)

I received an email from CH saying he planned to permanently disappear—it was indeed an abrupt decision. Thanks for your concern. -- SCZenz 07:14, 12 October 2006 (UTC)

There is something here which might be useful. --HappyCamper 15:27, 12 October 2006 (UTC)

Thank you both for your replies. You have resolved my concerns that the departure is genuine. There remains the great sadness that Wikipedia has lost yet another valuable editor over the same litany of concerns that many of us share. We feel so drawn to what Wikipedia could be, and so dismayed by what it is. --KSmrq^T 22:46, 12 October 2006 (UTC)

[edit] Mets501

Hi, I understand you feel strongly about unicode on maths articles (I disagree with you, but I'm not too bothered either way), but please avoid comments like "Get a clue before you shoot from the hip" that could easily be construed as a personal attack. thanks, and stay cool! (see also, my comment at Wikipedia_talk:AutoWikiBrowser#Mathematics_articles_and_Unicode) Martin 09:34, 13 October 2006 (UTC)

P.s. I hope that doesn't seem patronising! I just like to keep things friendly. Martin 10:46, 13 October 2006 (UTC)

Yes, it does seem patronizing, but you're forgiven. If you can alter the bot as you propose, the problem goes away. --KSmrq^T 11:56, 13 October 2006 (UTC)

[edit] Euclidean space edit

I see what you mean, I'm sorry. I'll fix it all now.--Rudjek 16:55, 21 October 2006 (UTC)

I've just reverted those changes. You see, the AWB will automatically unicodify articles unless set not to - I was not aware that it was an issue in those articles.Rudjek 17:04, 21 October 2006 (UTC)

Hmm. I also reverted. Anyway, thanks. It's been a recurring problem, and we've been promised a fix to the bot code to handle it. I tried to put a warning on the AWB project page in the meantime, but it was reverted. I’m guessing whoever took it out has not had the joy (?) of educating a new person once a week, as I have. --KSmrq^T 17:14, 21 October 2006 (UTC)

[edit] RefDeskBot

Hi - I've looked at the link you sent me, but I think the bot has worked fine. If you look here, the bot has removed all of the old questions before a certain date, putting them on subpages and transcluding them onto the archive page. This behaivoir is correct, so all the old questions are still there. If I've misunderstood, please tell me! Martinp23 14:46, 23 October 2006 (UTC)

Perhaps it was some strange transient. It seems to have left no permanent effects. At the time I posted, the October 17 entries, the first eight on the page, were duplicated. We'll just have to keep an eye out for future repeats. Thanks. --KSmrq^T 17:23, 23 October 2006 (UTC)

OK, thanks Martinp23 17:35, 23 October 2006 (UTC)

[edit] Irrelevant ramblings?

When referring to "Melchoir's ramblings", did you mean my contribution? If so, would you care to explain why this is irrelevant? If yoy did mean Melchoir, why did you remove my contribution? --Lambiam^Talk 10:46, 9 November 2006 (UTC)

The ramblings I mention are comments explicitly signed by Melchoir. I did not remove your contribution, nor that of anyone. I never saw your post, nor did I get a notice of an edit conflict. The servers seem noticeably slow, and Wikipedia glitches are known to occur under such circumstances. Please restore anything that disappeared! --KSmrq^T 11:02, 9 November 2006 (UTC)

As there was more than an hour's time difference between our edits, slow servers are a somewhat unlikely explanation for this glitch. In any case, I've restored it. --Lambiam^Talk 12:26, 9 November 2006 (UTC)

Slow servers can still be part what causes the problem to become visible, but there must be a bug in the server code, because it should have advised of an edit conflict under these circumstances. I don't have a timing audit trail of when I started and ended my edit, which might give a clue to the sequence. I do know that there was a substantial interval between when I started writing my post and when I committed it. For properly written software that should pose no difficulty, but I know it is not uncommon for lesser software to be confused by interweaving streams of actions. A simplified version of my stream would be: fetch current version of section to edit, preview my additions, save them. If the software is working properly, any change to the section (other than mine) between the time I fetch it and the time I save should raise an "edit conflict" event. Perhaps that's where the bug lies. It is also possible that your save happened before my fetch, but somehow the database was not properly synchronized, so I got an older version without your additions. (This is an obvious place for slow servers to have an effect.)

Bugs like this are a pain to debug, even for a single dedicated coder and a single piece of software. In this case we have multiple volunteer coders and multiple independent pieces of software. Plus we have a distributed system with caching. I'm afraid we're probably going to be living with this for some time.

One suggestion is that posts to talk pages and reference desks are rarely altered or removed. The exceptions are blatantly inappropriate posts (like vandalism, vicious personal attacks, and extreme profanity), and over-the-top full homework solutions. I don't expect you'll be making such posts, so if this glitch happens again just restore your contribution and maybe add a note about what happened. --KSmrq^T 20:09, 9 November 2006 (UTC)

[edit] =^def

Sorry for pestering you KSmrq. Are you saying that we should use things like:

...so we define blah to be

This is not what User:SebastianHelm is doing. He is putting =^def everywhere, and I really don't think he should be. --MOBle 20:45, 25 November 2006 (UTC)

Start a new section on the Project Mathematics talk page and bring this up. Give an example or two of the edits, and ask for clarification. Because, yes, in my view the decision was to use a plain equal sign with supporting text. Either I am mistaken or SebastianHelm is misguided; either way, community involvement should help sort it out. --KSmrq^T 21:24, 25 November 2006 (UTC)

[edit] Please behave

Your sneer in the direction of Melchoir in this edit on the Reference Desk was uncalled for. I'd appreciate it if you could moderate your comments and display a more collegial attitude. Thanks. Jitse Niesen (talk) 05:51, 30 November 2006 (UTC)

Sorry, Jitse, but I reject your characterization of my remarks as a sneer. What I said was

• I will refrain from saying Melchoir's answer is wrong, but take it with a grain of salt. There are efficient ways to compute a numeric result, despite the lack of a known closed form.

I stand by that claim. Mechoir doesn't like it. I don't give a damn. Facts are facts.

Many times when you or I or others post a response, someone amends or objects or nitpicks. Sometimes they're right, sometimes not. For example, recently I discussed fitting a rectangle inside a triangle. One reader responded with a "correction", which Lambiam then pointed out was wrong. Another response said the assumption of an isosceles triangle was unnecessary, and I pointed out that I had already covered that ground. I don't know if they read too quickly or I wrote too poorly or some of both, but I do not object to their effort to improve the answer, even if I end up wearing egg on my face.

Nor do I object to your voicing concerns about collegiality. I do not agree with your view in this instance, and it makes me feel uncomfortable, but I welcome your remarks and value your opinion.

I do strongly object to Melchoir censoring my remarks, and so I have restored my sentence. This is not a lecture podium where Melchoir — or anyone — is a god-like authority who cannot be corrected or challenged or extended. In the past he has objected vehemently to my pointing out his mistakes, and has refused to address them. I will not cater to that.

In this instance, he gave a response that could have been found by a brief web search. He assumes a limited meaning for "neat". You and I both appreciate numerical analysis enough to see that the numerical approach I sketch also qualifies as "neat". Hence my "grain of salt" caution.

Likewise, the last time he objected I also had substantially amended and extended what he had said. He had no further substance to add, nor corrections to my additions, despite my repeated requests that he focus on facts and stop looking for slights.

Melchoir has no right to censor me. In fact, he should be blocked if continues to do so.

How would you like it if I slapped duct tape across your mouth anytime you said something I didn't appreciate? I would not do that to you, nor even to Melchoir. I do not appreciate him doing it to me.

For comparison, I quote the following recent exchange involving two other parties:

---

Dear 83.100.138.7/83.100.174.103/83.100.250.33/83.100.250.53/83.100.253.24/87.102.12.129/87.102.16.174/87.102.36.82/87.102.36.159, perhaps you should verify (1) that you know what you are talking about, and (2) that your contribution adds value, before you react to the attempts of other editors to answer the questions posed here. Thus far your contributions have succeeded in creating more confusion than enlightenment. --Lambiam^Talk 09:04, 27 November 2006 (UTC)

ok I'll fuck off then. 87.102.20.219 16:28, 27 November 2006 (UTC)

---

That is considerably more harsh than anything I have said with regard to Melchoir's few, brief posts. I did not object, and I see no evidence that you or anyone else did either. To the contrary: although I might try gentler phrasing, I agreed with the sentiments Lambiam expressed.

I wish to point out that my second sentence supports what Melchoir said, as far as it went. Apparently he had no interest in censoring that. I also point out that I have amended and greatly extended posts by many others. Yet only Melchoir objects and now censors me.

I respectfully submit that somebody (other than me) take Melchoir to task, and teach him to either accept responses he does not like or stop posting. Unfortunately, my many interactions with him suggest he has adopted an extreme anatomical position that causes him to view the world through his navel, if you catch my meaning.

Finally, since Wikipedia is a cooperative effort, and since I am willing to trust your diplomatic instincts, if — having absorbed my views — you would like to substitute an alternative first sentence, please do so with my blessing. Just add a parenthetical remark at the end that we have reached such an accomodation. --KSmrq^T 08:55, 30 November 2006 (UTC)

Of course you're welcome to try and improve Melchoir's (and others') replies, and I hope you'll continue doing so. As I'm sure you realize, my issue is solely with the way you correct Melchoir, specifically the first sentence. I thought a bit about it and the points that jar me is that you name Melchoir, that you say his answer is wrong, and that I don't agree with that. I know you didn't quite say his answer is wrong, but that is how your remark is interpreted.

I think that you wouldn't have used those words if you were amending somebody else's reply. I don't remember your using such harsh language, except in the previous case involving Melchoir, something with cycle notation. I didn't like your language then and I was not the only one (Gandalf and Salix Alba said something along these lines), though at that instance I agreed that Melchoir's reply was extremely confusing for the guy that asked the question.

You're correct that Lambiam's remark is much harsher. However, you're quite wrong in trusting my diplomatic instincts. Nevertheless, I had a go at it. I tried to make my change minimal and thus it's still harsher than I'd like; I'd have prefered it if you just hadn't included the first sentence. -- Jitse Niesen (talk) 12:35, 30 November 2006 (UTC)

New facts seem to have rendered the wording obsolete; I found a citation of a closed formula — maybe. If that stands, our article is wrong, not just Melchoir. If not, I'll be a little embarrassed, which I can live with. So I have changed the wording again, and added more info.

I'm willing to discuss human issues, and sometimes we must; but I find that it's often most productive to continue to bring attention back to the technical challenge. Watch champion olympic ice skaters; I am always impressed to see one flub a landing in front of the world with the competition on the line, yet continue the program as if nothing had happened. Or watch an American football quarterback throw an interception, then come back and pass for a touchdown. Remind participants that we're trying to answer a reader's question and maybe educate others at the same time, and that we're trying to write an encyclopedia to serve the world. And now and then get a laugh, or at least a smile. --KSmrq^T 15:47, 30 November 2006 (UTC)

I did not remove any content from your refdesk post; I removed only the attack. By attempting to hide your incivility quietly, I thought I was doing you a favor. But the next time you say that I've got my head up my ass, I will start handing you the relevant warning templates. Please consider that it is in everyone's best interests if you refrain from that kind of behavior. Melchoir 18:14, 30 November 2006 (UTC)

Since you choose to eavesdrop on a side conversation, let me address a few words to you personally. To the best of my knowledge we have never met in person. If we did, I wonder if you would act as you do here. Since early days, Internet discussions have spawned vitriolic flame wars that rarely happen face-to-face. Participants cannot see a twinkle in the eye, nor hear a tone of voice; nor do they register the emotional impact of their remarks, nor physically occupy the same room.

If I walked up to you, looked you in the eye, and went over the same list of errors I once posted for you, I suspect you would feel extremely uncomfortable ignoring them as you did. You would listen and respond. And I seriously doubt you would try to threaten me as you have here, not if we were alone, and not if a community stood around us.

But here you act like a child, and a coward, and a bully. You visit my personal talk page, read my private remarks to someone else, see an oblique complaint, take explicit offense, and threaten me with warning templates! Do you have any idea how absurd that looks? Surely this is not the real you. At least, I hope so.

I have devoted a great deal of my life to effective technical communication. I try to employ that experience to the benefit of Wikipedia and those who read it. I hope everything I write is correct, clear, and compelling, but I know I will not always succeed. Therefore I listen to others, even if I disagree or don't like what they say. In my experience with you, you do not, and it is getting in the way of our work here.

I am trying to blame your repeated touchiness and intransigence on the limitations of the medium, not on your personal limitations. If it will make you feel better, the next time I make a mistake, feel free to hold me up to public ridicule; I promise I will not respond with threat templates, but will let everyone know I do not object. Here is a fine opportunity.

Whatever it takes, prove me right. Prove you are able to put the good of Wikipedia and all our readers to the fore. Prove you are smart enough to beat the obstacles imposed by the medium. Prove you are wise enough to embrace correction. Prove you are a mensch. --KSmrq^T 01:18, 1 December 2006 (UTC)

In fact, I will not even respond to most of what you have said just now, as you insist on making your claims dozens at a time without pause for discussion. I wonder if you really believe that delivering speeches at people is an effective way at getting them to listen to you.

I will address what actually matters: I have no intention of holding you up to ridicule. I ask only that you cease to attempt to do the same to me. We are not competitors. Now, if you don't like the social norms of Wikipedia and the mechanisms by which they are enforced, tough. There is no wiggle room in Wikipedia:No personal attacks, and there is no excuse for escalating a conflict by insult. Don't do it. Melchoir 07:34, 1 December 2006 (UTC)

First you attempt to censor my public remarks. Then you try to control my personal discussions. What next; will you claim that Wikipedia has granted you the authority to decide what I may think?

Unlike you, I do not presume to give orders. Instead, I will just remind you of "the fundamental rule of all social spaces": Don't be a dick.

I did not literally say you had your head up your ass, but you seem determined to demonstrate that you literally do. You come to my talk page looking for insults. You threaten me. Again, and again, and again. I offered you an opportunity to save face and work towards the common good. This is how you respond.

Apparently it does not matter how I address you. It does not matter whether I am brief or wordy. It does not matter whether I am cordial or brusque. I know, because I have tried many times, many ways. You always find some excuse to say you need not listen, you will not listen.

If you feel ridiculed, try asking yourself if just maybe it has nothing to do with me; just maybe it is because you are afraid you are ridiculous. But so what if you are? What if it turns out you are one of the greatest fools ever to walk the planet. Well join the club; we all are. Get over it.

Surely you can find better uses for your time than accusing me of personal attacks and trying to intimidate me. How's it working for you so far? Are you having more fun and being more effective? Are you feeling less insulted?

Look back at the thread on the help desk that set you off. It's moved on without you, productively. Even the first sentence, to which you objected, has changed. I suggested that Jitse rewrite it to his diplomatic tastes, which he did. Then I rewrote it again in light of new information I was able to turn up. And as a result of the discussion in the thread, we also have an improved article, with new content and new references. Meanwhile here you are, bristling over history.

Based on past behavior I don't really expect you to absorb or accept or even acknowledge anything I have said. Perhaps you're afraid to; I really don't know. But I can hope it will do some good anyway — if not for you, then for someone else. --KSmrq^T 14:42, 1 December 2006 (UTC)

If you're not going to be civil, then there will be no enlightened discussion between us. I have a great deal to say, but if anyone wants to hear it they will have to talk to me instead of writing essays about me. If you want to bring an issue to my attention and hear what I think about it, then say it, type four tildes, and wait. I think you're much more interested in reassuring yourself with your own tirades than in actually sharing information; why don't you try to prove me wrong? Melchoir 16:07, 1 December 2006 (UTC)

Wow! Who could have guessed you'd come up with an excuse to dismiss everything I said? Oh wait; I did.

Want an issue? Correction ≠ incivility. Live with it. QED --KSmrq^T 09:49, 2 December 2006 (UTC)

P.S.: And now for some enlightenment.

• Q. Why won't cannibals eat clowns?

  A. They taste funny.

• Q. What do you call a cat tossed out of a car?

  A. Kitty litter.

Enjoy. --KSmrq^T 09:49, 2 December 2006 (UTC)

That's a great issue. Let's hypothesize that, at some point, I need to be corrected. There are civil ways to make a correction, and there are uncivil ways to make a correction.

You want to assert that I'm wrong? Then reply to me with "No, you're wrong". Be direct. It's what everyone else does.

Don't talk about me, in my virtual presence, and tell someone else to ignore me. Do you understand why this behavior is inappropriate? Melchoir 10:35, 2 December 2006 (UTC)

Again with the orders!?! Well, my talk page, my rules. So far our discussions have been, for me, tedious, annoying, and wildly unproductive. I'd like that to change. So, from now on if you want a response from me here, first tell me a good joke. It can be a one-liner or a shaggy dog story, squeaky clean or slightly risqué; just make it funny, and no repetition allowed. If you don't have a sense of humor yourself, you can get someone else to help you. It's your choice how you proceed; but no joke, no response. Make 'em funny enough and I might even come to look forward to hearing from you. --KSmrq^T 11:23, 7 December 2006 (UTC)

Fine, we'll even go with the theme. Knock knock. Melchoir 15:43, 7 December 2006 (UTC)

Right! Who's there? (By the way, I'm also busy with other things, so you may not always get an immediate response.) --KSmrq^T 15:47, 7 December 2006 (UTC)

Controlling, okay now you say "Controlling who?"

(pause)

If you have a problem with imperative sentences, I can certainly do my Patronizing Melchoir act. It's how I deal with the newbies, and I've had lots of practice. Your call. Either way, I hope you're not the kind of person who refuses to do the right thing because he's been told to do it.

But enough meta. I asked a question... Melchoir 15:55, 7 December 2006 (UTC)

[edit] Etiquette

I'll take it as an honest mistake, but be careful to check that you don't remove other poeple's comments on discussion pages, it could get you into a lot of trouble. Thanks. yandman 10:11, 7 December 2006 (UTC)

I don't know if it is an honest mistake or not, but it is not my mistake. I wish I knew what the @#!$ is going on with the MediaWiki software, but this highly annoying (to me and you both!) bug has struck repeatedly. As on every previous occasion, the first I hear of it is when some irate person complains to me about my edit. And every time I patiently explain that I did everything right, that I never saw their message, and that I never got a warning of an edit conflict. I am deeply sorry for your loss; please, put your comment back in the discussion. (And if you really like good etiquette, say "excuse me" for the false accusation. :-D ) --KSmrq^T 10:58, 7 December 2006 (UTC)

Ahhhh... My apologies. You wouldn't be using the google toolbar perchance? yandman 13:14, 7 December 2006 (UTC)

Apology accepted! No, I was not using the Google toolbar, nor anything else exotic. That edit was made using Mozilla 1.7.13 and Windows 2000. And I don't recall anything that distinguished it from any other edit. I do have the habit of beginning an edit and taking a long time to complete it. That is, I start writing, and as I proceed I use auxiliary applications, search the web, and look at other Wikipedia pages. Also, I do frequent previews, then use BACK in the browser to continue editing. That shouldn't confound the MediaWiki software, and I don't imagine I'm the only one to work this way. If you run across any explanations, I would love to hear about it! --KSmrq^T 13:35, 7 December 2006 (UTC)

[edit] Etiquette Revisited

I am going to assume that your removal of my comments Wikipedia_talk:WikiProject_Spam#cut-the-knot.org was another glitch and not done deliberately. I do not appreciate, however, your comments: "Any attempt to broadly classify cut-the-knot links as spam is misinformed and misguided." The edits speak for themselves. If you don't like the guidelines and WP's classification of link spamming, then make your comments there and try to change the guidelines. They are created by other editors just like you and I. If you don't agree with someone else's opinion here on WP, please refrain from demeaning the other person's comments with statements like these. I don't agree with your classification of these links, but I'm certainly not going to insult you with a derogatory remark like this. Calltech 22:55, 12 December 2006 (UTC)

Ah, perhaps you read the section immediately above! Indeed, I did not deliberately remove any comment of yours, or have any indication to that effect. Thanks for your understanding.

As for the content of my remarks, it appears that other editors have the same high opinion of the site as I expressed. This is my first time commenting on the spam page, so I don't know how people usually word things. But, Wikipedia guidelines surely are not meant to rule out multiple links to a high quality source. --KSmrq^T 18:02, 13 December 2006 (UTC)

[edit] Differentials

See Wikipedia talk:WikiProject Mathematics#Symbol for differential please. JRSpriggs 10:27, 20 December 2006 (UTC)

[edit] Mathematics and God

I've added the "{{prod}}" template to the article Mathematics and God, suggesting that it be deleted according to the proposed deletion process. All contributions are appreciated, but I don't believe it satisfies Wikipedia's criteria for inclusion, and I've explained why in the deletion notice (see also "What Wikipedia is not" and Wikipedia's deletion policy). Please either work to improve the article if the topic is worthy of inclusion in Wikipedia, or, if you disagree with the notice, discuss the issues at Talk:Mathematics and God. You may remove the deletion notice, and the article will not be deleted, but note that it may still be sent to Articles for Deletion, where it may be deleted if consensus to delete is reached, or if it matches any of the speedy deletion criteria. Ioannes Pragensis 10:50, 22 December 2006 (UTC)

[edit] ISBN 13s

The problem with listing many is that users won't know which one to click on. Rich Farmbrough, 13:41 23 December 2006 (GMT).

[edit] Snare technique

Hello. You write that this article is "not eligible for prod (see history)". Apparently this has come up before and one person didn't feel that it should be deleted. Does that mean it's ineligible for deletion forever? Can I ask why? Thanks. Brad Halls 04:55, 28 December 2006 (UTC)

Articles can be deleted in three ways: SPEEDY, PROD, and AfD. Speedy deletion requires no debate and no waiting, and is used for things like blatant spam, vandalism or copyright violation. A PROD deletion requires a waiting period, but bypasses debate; any objection makes an article ineligible. That still leaves the AfD process, where arguments are made for and against deletion in an announced public discussion. The history of the snare technique article includes a previous PROD and objection, so debate is necessary. It also appears to have supporters and some active editing. Since deletion will not occur unless there is a clear consensus to do so, and since a number of editors have indicated by their actions that they feel this is a worthwhile article, my guess would be that it would survive AfD. My recommendation would be to spare everyone the trouble; just let the article persist, even if it is not entirely to your taste. The same goes for Moeller method. If you would like to see the article expanded or improved, give specific guidance on the talk page for what you want. Many editors feel that deletion is a fairly drastic step, to be reserved for articles that clearly harm Wikipedia; this is a personal decision, but a sentiment worth taking into consideration. --KSmrq^T 06:57, 28 December 2006 (UTC)

[edit] Thanks for Helping ... and sorry for mistaking someone else for your efforts

Hi KSmrq,

I wanted to thank you for going that extra mile in my question about the equation of a line, by explaining how to generate a point using another equation when the slope is 0. And I'm sorry I mistook your work as someone else's. I think when you said "as StuRat has indicated," I somehow read that as his signature (it was 1 AM when I replied, my eyes were obviously not working.) I think I understand how to use the parametric equation for the line now.

Thanks again (and sorry),

Alex Ng 19:59, 30 December 2006 (UTC)

I guessed as much about the source of confusion, since I was in about the same state when I wrote it. :-)

The psychology of understanding is sometimes amusing: Before, a topic is opaque; after, obvious. Sometimes those who have gotten to the "obvious" side forget what it was like before. I'm glad the explanation worked for you. --KSmrq^T 20:46, 30 December 2006 (UTC)

[edit] Fixing redirects; and also archiving

You moved Hamilton–Jacobi equation changing a hyphen to an ndash. I noticed that you tried to fix the doubled redirects at Action (physics) (which is OK as far as it goes). But the more effective way to fix them is to look at "What links here" at the article itself (HJE) and edit just the redirected redirects. Do not waste time editing the original pointers in the articles. I cleaned it up in this case, but I am telling you so that you can do it right next time you move a page.

Also your talk page really needs to be archived. It is much too long. JRSpriggs 08:54, 8 January 2007 (UTC)

I've heard the archiving comment before; you can find it somewhere on this page. ;-)

If you know a way to search all the archives for a page as easily as searching one page, maybe I'll do it.

I thought I was only fixing double redirects, as my edit comments said each time I did it. First I moved the page. Then I asked to see all the links. Most of those links were to the name with a dash and no plural. One of those was the redirect from the name with a dash and a plural. I only fixed the pages linking to that plural name, since those seemed to be the only doubles.

The "action (physics)" article required the most fixing, but it essentially followed this pattern. For example, I changed

• "[[Hamilton-Jacobi equations]]"

to

• "[[Hamilton–Jacobi equation]]s"

Notice the subtle shift of the final "s", along with the change of hyphen to en dash.

In other words, after the move but before the fixes, "action (physics)" linked to "Hamilton-Jacobi equations" — with hyphen and plural — which redirected to "Hamilton-Jacobi equation" — with hyphen and singular — which redirected to "Hamilton–Jacobi equation" — with dash and singular, the new location of the article itself. If I had not been lazy, I would have edited all the links that used a hyphen, whether double redirects were involved or not, to incorporate the preferred typography. Ironically, I also neglected to change the typography in the article itself (which I have now done).

But somehow I missed the five redirects you fixed:

1. "Hamilton-Jacobi equations"
2. "Hamilton-Jacobi equations of motion"
3. "Hamilton-Jacobi theory"
4. "Hamilton-Jacobi Equation"
5. "Hamilton-Jacobi Equations"

I'm not sure how that happened. Thanks for catching and fixing my slip. I'm glad I don't do this kind of bookkeeping often! --KSmrq^T 11:04, 8 January 2007 (UTC)

You are welcome. If you look at Wikipedia talk:WikiProject Mathematics, you will see that it uses Template:Archives which is invoked by " {{archives|width=100px}}". And the associated archive list file contains "[[Wikipedia talk:WikiProject Mathematics/Archive Index|Complete]]". Somehow (thanks to AzaToth (talk • contribs)) this allows you to look at the totality of the archives at once. JRSpriggs 06:03, 9 January 2007 (UTC)

[edit] Sorry !

Apologies for interjecting my response in the middle of yours on the Mathematics RD - I had mistakenly assumed that the two paragraps in your response were from two different editors ! Anyway, I have now removed my comment. Gandalf61 15:52, 11 January 2007 (UTC)

[edit] Computer algebra systems

Hi KSmrq,

First, I would like to thank you for your work on the maths reference desk. I've read the refdesk regularly for about a year, and am deeply impressed with the way you respond to questions, whether they be on elementary or advanced topics, always with the same patience and insight. A tiny number of questions have been mine, such as this one. Thank you!

Second, I would like to ask your advice about selecting a computer algebra system. I remember your having stated in passing that you used a CAS when arriving at a certain conclusion, and I also believe that you once said that you were a supporter of free software (I'm certain about the first statement, not 100% certain about the second one). I've read the CAS article, and am aware that there are several open source computer algebra systems.

Some background: I'm certainly no mathematician, but from time to time, mostly for the fun of it, do some algebra. Having a CAS available might to help me from doing silly mistakes, and from spending a lot of time in spotting them. Right now, I'm trying to gain a little more insight into mathematical statistics, involving the need of both symbolic and numerical integration. I had access to Maple some time ago, and have also used a trial version of MuPad. Both programs would fit the bill, but I'm looking for a free, open source alternative. For plotting, simulations and computations, I use R. I would greatly appreciate your opinion about whether there are open source alternatives that could be useful to me, and if so, where to start. Thank you. --NorwegianBlue ^talk 21:35, 11 January 2007 (UTC)

PS. The OS'es that I currently use are Windows XP and Kubuntu 6.06. --NorwegianBlue ^talk 10:05, 13 January 2007 (UTC)

I am an enthusiastic user of computer algebra systems. The landmark original Macsyma system (not the current commercial one) evolved at the MIT AI Lab, which is also where Richard Stallman and the "hacker mentality" of free software began. So, despite the high-priced efforts of Wolfram and Mathematica, CAS and open source are a natural combination.

One interesting effort you might like to explore is SAGE: Software for Algebra and Geometry Experimentation. You can find a home page at http://sage.math.washington.edu/sage/, and download versions for XP and Linux. It incorporates a number of open source projects; and you can find more at Category:Free computer algebra systems. --KSmrq^T 21:40, 13 January 2007 (UTC)

Thanks a lot, I'll try it out as soon as the download finishes! --NorwegianBlue ^talk 10:56, 14 January 2007 (UTC)

[edit] Continuity and Givens rotations

I appreciate your recent edits to Givens rotation, as (almost) all your edits. I'm intrigued by your reference to continuity, but I couldn't find it in the report by Anderson and Fahey after a quick scan. Could you please direct me to the correct page? I assume that you know the report well and that my request won't consume too much of your time. All the best, Jitse Niesen (talk) 08:40, 20 January 2007 (UTC)

"Almost"? Oh my.

Yes, the continuity idea is relatively new. I am working on a massive rewrite of the rotation matrix article, and needed the Givens rotation article improvements to support it. As you suggested, I checked the note I cited and found it was not the right one. I have replaced it with two other LAPACK notes, one by Anderson and the other by four authors including Kahan. The latter is even more thorough about the computation than Anderson (whom they cite), and the article should probably use it instead. Perhaps you'd enjoy absorbing the content and making the revision. If not, I'll try to get back to it.

I have long resisted editing the rotation matrix article because I know too much. Inevitably the ignorant hordes will descend, and I will see my attempts to be clear, correct, and complete be reduced to rubble. Practically, I have more incentive to reserve this writing for my professional life. It's odd, but when you give things away, people treat them as worthless; when you sell them or limit distribution to formal channels, the perceived worth shoots up and the author gets much more respect. Yet knowing that, I still write for Wikipedia, partly to pay back all the free sources of education in my life and the assistance I received in covering private university expenses. --KSmrq^T 15:04, 20 January 2007 (UTC)

Gah; I should stop second-guessing myself. Dates notwithstanding, it is the Anderson note that cites the other note. He points out that, for all their care, they left in discontinuity. Therefore, the algorithm I put in the article is (I hope) the preferred one. Sorry for the confusion. I studied all this in detail some time ago, came to this conclusion, squirreled it away for future reference, and now am trying to retrace my reasoning. But if you would like to second-guess me, please read the two notes yourself, maybe do some experiments and analysis, and reach your own conclusions. I would value an informed second opinion. Givens rotations are a workhorse, and either of these algorithms will do a better job than a thoughtless implementation. --KSmrq^T 15:30, 21 January 2007 (UTC)

[edit] Koch's snowflake

Hello I saw you replied to a question about Koch's snowflake on the reference board, and since I really liked your style of explaining, I hope you won't mind me putting this question on your user comment page. I have this formula for finding the area of a stage of the snowflake (sorry, I am not familiar with the wikipedia formula thing, but hopefully it will be fine in this format): ( sqrt(3))/(4) + ( sqrt(3))/(12) *(( (9)/(5) ) - ( (9)/(5) )*( (4)/(9) )^(n))

This gives the area for the nth stage of the model. What I need to find out however, is how to derive this formula. I hope it's not too much bother for you, and don't worry if you cannot find the time.

Edit: And this is for when the original side length equals 1, also showing l when n is 0 in the formula would also be nice, but not in any way required. (Im just aiming to understand this)

Thanks 213.167.126.215 16:39, 24 January 2007 (UTC)

It would be better to ask at the mathematics reference desk, for several reasons. If I don't get to it soon (which seems likely) you may still get an answer. Whoever answers, others can check for correctness and completeness. And any benefit from a good answer will be shared by a wider audience. --KSmrq^T 20:19, 24 January 2007 (UTC)

[edit] Help with rotation matrix

Perhaps you can help me, or point me in the right direction. We had some discussions on the orthogonal matrix page, and I am still trying to understand some points about rotation matrices. (3x3 real representation of SO(3)).

• Am I correct in saying that EVERY rotation matrix can be expressed as exp(A) where A is a 3x3 real skew-symmetric matrix?

• If thats not true forget the rest of this. If it is true, then if R=exp(A) is a rotation matrix, I can say (dR/dt) = (dA/dt) R, or and then .

• I can express a rotation matrix R in terms of the Euler angles (α, β, γ), and I am looking for the corresponding A matrix. Using the above procedure, I can get the straightforwardly:

where

and these are verified in a number of references ([Ax, Ay, Az]) is the angular velocity pseudovector.)

• Still trying to find A, I look at the above and say, for example that

and make the identification

The problem is that these aren't compatible. I should get

or

which is not true in general.

Now I'm lost. It seems like this means there is no such A. Something to do with "integrability" but I'm vague on this.

Could you help me, maybe point me in the right direction regarding this problem, given that I am a physicist, and not a mathematician? Even an explanation that is over my head is ok, because then maybe I can research the words that you use.

Thanks for any help you can give - PAR 21:51, 24 January 2007 (UTC)

My, that's a lot to answer! As it happens, I am in the process of writing a completely new rotation matrix article, and some of your points I have already incorporated.

So let's start with the basic exponential map. The answer is "yes", but let me make it memorable. Let R(t) be a rotation matrix which is a continuous function of t, and which is the identity matrix when t is zero. (The dimension of R can be n×n, not just 3×3.) Because R is necessarily an orthogonal matrix, it satisfies I = R^TR. Differentiate both sides with respect to t, and then let t equal zero.

In Lie group theory, we have just shown that the tangent space at the identity for SO(n) consists of n×n skew-symmetric matrices, A^T = −A. If we add a bracket operator to this vector space, we get the Lie algebra for the group. And the exponential map gets its name because for all subgroups of a general linear group, GL(n), it is just the matrix exponential. There is one important detail not yet covered, but it does no harm here; both SO(n) and O(n) have the same Lie algebra, but the exponential map can't reach any of the matrices with determinant −1 because they are not continuously connected to the identity. (We cannot "gradually reflect"!)

Where you go next I cannot follow; it looks confused.

A general fact about Lie groups is that any neighborhood looks like a copy of a neighborhood at the identity; we simply multiply by a group element to position a copy. Confusingly in the context of rotations, this is called "translation"! But this fact helps explain why the Lie algebra tells us almost everything about its associated Lie group.

If we use Euler angles, then R is a function of three angles. But now we must be precise, because there are many different conventions called "Euler angles", 24 of them! For some of them the identity matrix would correspond to all zeros, but for others that is not so.

I'm guessing that your goal is to find a convenient expression for the derivative of an arbitrary 3×3 rotation matrix expressed in terms of Euler angles. If that's so, let me know.

I rarely have anything to do with Euler angles, because quaternions are (usually) much cleaner and simpler. They can be viewed in many different ways, all helpful. One view is that they are a slight variation of an axis-angle parameterization. The unit quaternion

with u = (a,b,c) a unit vector, can be more simply written

and represents a rotation by 2θ around the axis u. But this is also a point on a unit sphere, S³, in four-dimensional space.

The derivative of a curve passing through the identity, [(0,0,0),1], is a vector uθ, essentially an angular velocity. And we can move that derivative to an arbitrary quaternion q by a quaternion multiplication. Are you beginning to see the natural parallels to the matrix version? The advantage is, it is so easy to think on a sphere, compared to some abstract space of matrices.

If you have access to a decent library or bookstore, two books you might find helpful are Structure and Interpretation of Classical Mechanics (ISBN 978-0-262-19455-6) and Geometric Algebra for Physicists (ISBN 978-0-521-48022-2). If you want to really come to grips with rotations you need to look at the Spin groups that are their universal cover, and the nicest approach to Spin groups is through Clifford algebra, which is what Geometric Algebra interprets. Unit quaternions are the Spin group for SO(3), which is one reason they are so helpful. --KSmrq^T 02:28, 25 January 2007 (UTC)

Thanks for the explanation, I will have to think about what you wrote. It helped me because I concentrated on the point where you lost my train of thought, and realized my mistake was there - I was wrongly assuming:

Regarding your edits to the rotation matrix article - GOOD, it needs some work. The Euler angle section is wrong and I am trying to fix it.

Regarding my original problem: The bottom line is that I have a rotation matrix which is expressed explicitly in terms of the Euler angles, call it R(α,β,γ). If it can be expressed as R=exp(A) then I want to find A, given that I know R. (I am not looking for dR/dt or dA/dt, I am looking for A.) PAR 04:08, 25 January 2007 (UTC)

OK, I can show you how to find A. It's conceptually simple, but with Euler angles it won't be pretty.

We need to understand how the exponential works. It takes a tangent vector (which here is a skew matrix) of a given length and direction, and it shoots out from the identity. For a 3D rotation, the direction is the rotation axis and the length is the rotation angle. In other words, the skew matrix is like an angular velocity vector. Explicitly,

where u = (x,y,z) is a unit vector, corresponds to uθ, and exponentiates to a rotation around axis u by angle θ. (We should stop and observe that if we negate both the axis and the angle, we get the same result.)

It is not difficult to extract u and θ from R, but as functions of Euler angles producing R, yuck. (Contrast that with quaternion q = [u sin ^θ⁄₂,cos ^θ⁄₂], for which the conversion to uθ poses little challenge.)

Keep in mind that the exponential always shoots out from the identity. If you want to know how R is varying as a function of the Euler angles, to find a derivative of its change, then A will not do the job. Yes, there is a tangent space at any given rotation, R; and, yes, we can "translate" the tangent space at the identity to R. However, different paths of getting from I to R will parallel transport the tangent space to align in different ways. We get spoiled by flat spaces where this transport problem does not occur. --KSmrq^T 15:48, 26 January 2007 (UTC)

Ok this is good. I understand enough of what you are saying to believe that with some thinking I will get the rest. Thank you for your help, and I hope I can bother you again if I get stuck. Also, I will put the Euler rotation matrix to Mathematica and try to diagonalize it and see how yucked up it is.

PS - Also - I ordered the book "Structure and Interpretation of Classical Mechanics" PAR 23:54, 26 January 2007 (UTC)

[edit] Ed Pegg, Jr.

I restored the Ed Pegg, Jr. article and nominated it for deletion at Wikipedia:Articles for deletion/Ed Pegg, Jr. to see what community's opinion would be. Oleg Alexandrov (talk) 16:12, 31 January 2007 (UTC)

[edit] One or more

Hi, thank you for your contribution to Rotation - "one or more" is plural. See for example Bartleby → friedfish 16:54, 20 February 2007 (UTC)

The sentence in question is

• In roller coaster inversions the rotation about the horizontal axis are one or more full cycles, where the centrifugal force keeps people in their seats.

The subject of the sentence, with which the verb should agree, is "rotation", singular. So I am again reverting your mistake. Please do not introduce it again. Thanks. --KSmrq^T 17:04, 20 February 2007 (UTC)

[edit] Happy Pi Day!!

Happy Pi Day KSmrq! Having any Pi today? :) You are a great teacher! [Mαc Δαvιs] (How's my driving?) ❖ 07:37, 14 March 2007 (UTC)

Pi Day? Who knew? I suppose if we time it just right we can get it down to the second. :-)

A little web searching turned up PiDay.org, which has one of my favorite π remarks, by Unix guru and two-time Academy Award winner Tom Duff: "pi seconds is a nanocentury." In my youth I memorized π to at least 80 decimal places, just for fun; I approached it like learning poetry. (I've never once needed all those digits.) More recently, I rewrote the area of a disk article at the urging of Michael Hardy, and closely studied the approach of Archimedes for the first time. I don't obsess over π, but every time you turn around, there it is. ;-)

One secret to my teaching is that I am a slow learner. By the time I figure it out, I can explain it to anybody! (My impression is that many people never attempt real understanding; they settle for memorizing something they can repeat.) Another positive factor is enthusiasm. So I thank you for the compliment, and encourage you to absorb what you like and pass it on. --KSmrq^T 08:39, 14 March 2007 (UTC)

Only in the US! In the UK, we celebrate pi day on 22nd July ;) Geometry guy 15:15, 22 March 2007 (UTC)

[edit] Graph

Nice edit to function (mathematics): a small change perhaps, but now the graph illustrates key concepts in the article, such as domain, codomain and range, in a more effective way. Geometry guy 15:15, 22 March 2007 (UTC)

Thanks. I had suggested this on the talk page some time ago, and the recent rewrite of the intro inspired me to go ahead and create it.

It took more effort than I anticipated, in part because of the vertical tangent at the left boundary. The usual output of plot software is a series of line segments, which for this example I found visually deficient. Since I intended to produce SVG, so that the image could be smoothly scaled to any size, I decided to replace the piecewise linear fit by a piecewise cubic Bézier curve fit; this ensures the graph will never have visible discontinuities.

I just hope other editors approve as well, so the extra trouble pays off. --KSmrq^T 18:15, 22 March 2007 (UTC)

I approve, it's much better. A TeXnical question: you wrote f \colon [-1,1.5] \to [-1,1.5] in the caption, where I'd write f : [-1,1.5] \to [-1,1.5] . Is this on purpose? If I remember correctly, the symbol : is typeset as a relational operator and \colon induces some other spacing, and I like "my" version better. If you don't know it off hand, don't bother about it; I'll look it up in some TeX books. -- Jitse Niesen (talk) 00:40, 23 March 2007 (UTC)

Thanks. Yes, I deliberately wrote \colon because that is what Knuth says to use in exactly this context. From the TeXBook:

• If you want the ‘:’ character to be treated as a punctuation mark instead of as a relation, just call it \colon:

f:A\to B	⇒
f\colon A\to B	⇒

He gives another example of this same usage later, making it even more clear that the ‘\colon’ form (treated as punctuation), not the ‘:’ form (treated as a relation) is what he intends to be used here.

Knuth "went to school" on technical typesetting, studying best practice, before he developed the rules and conventions of TeX. The man is nothing if not thorough! He only mentions \colon twice in the TeXBook, both using this kind of example, so I assume he studied this situation and felt that it demanded punctuation spacing. --KSmrq^T 03:37, 23 March 2007 (UTC)

[edit] Plücker (and Grassmann) coordinates

Hi there, I found some of your comments on the Plücker coordinates discussion page. I was actually quite a bit put off by the article itself: in algebraic geometry these days no one talks about Grassmann coordinates, and everyone would scratch their head if you told them that Plücker coordinates apply to Gr(2,4) only! I was also fairly surprised to learn about an apparently large subculture of (computer graphics?) people who do all sorts of elementary things with this special case, with the attendant terminology. Maybe, the content can be moved to Plücker coordinates (three dimensions) page and an article expounding on the general grassmanian case put in its place, with disambiguation in the beginning? From a mathematician's point of view, it seems like a natural thing to do. What do you think? Arcfrk 12:38, 24 March 2007 (UTC)

Greetings, and thanks for stopping by.

I say the algebraic geometers you refer to are being sloppy, lazy, and historically inaccurate. In other words, typical mathematicians. ;-)

W. V. D. Hodge and D. Pedoe, in Methods of Algebraic Geometry, ISBN 978-0-521-46900-5, entitle their Chapter VII of Book II "Grassmann coordinates", and say in their bibliographical notes:

• The use of coordinates to distinguish linear spaces originated with Grassmann and was developed into line-geometry by Plücker. References will be found in the article by Segre (7), and an account is given in Bertini (3). Properties of determinants which are in effect Grassmann coordinates play an important part in the algebraic theory of invariants. The basis theorem of §7 was first proved by Mertens. Our proof is similar to that given by Weitzenböck [Proc. K. Akad. Wetensh. Amsterdam, vol. XXXIX, p. 503 (1936)].

The citations in question are

• (3) Bertini, E. Geometria Proiettiva degli Iperspazi (Messina, 1923).
• (7) Ency. der Math. Wissenschaften, III, C 7, C. Segre.

And Segre cites

• H. Graßmann, Die lineale Ausdehnungslehre, ein neuer Zweig der Mathematik. Leipzig 1844 == Ges. Werke, 1. Bd., 1. Teil („A₁‟).
  —Die Ausdehnungslehre. Berlin 1862 == Ges. Werke, 1. Bd., 2. Teil („A₂‟).

I did not find a copy of the Grassmann works online; the best source is probably Hermann Graßmanns gesammelte mathematische und physikalische Werke, edited by Engel.

J. G. Semple and L. Roth, Introduction to Algebraic Geometry, ISBN 978-0-19-853363-4, another older work, also refers to "Grassmann coordinates" (page 295). Robin Hartshorne, Algebraic Geometry, ISBN 978-0-387-90244-9, is one of the standard works taught these days, but seems to be mute on this topic. Phillip Griffiths and Joseph Harris, in Principles of Algebraic Geometry, ISBN 978-0-471-05059-9, another standard modern reference with somewhat different concerns, introduce the general coordinates in §1.5 (page 194), but without a name! Later (page 209) they discuss the Plücker embedding of a Grassmannian in a projective space via a Plücker map, so perhaps the attribution spills over (incorrectly, of course).

By far the most complete discussion that I have found (in English) is Hodge and Pedoe; perhaps you have other good sources. But modern concerns are so different from classical ones, and so diverse, that few modern authors would take much interest in exploring these coordinates for their own sake.

• Dieudonné, J. (1972), "The Historical Development of Algebraic Geometry", American Mathematical Monthly 79 (8): 827–866, DOI:10.2307/2317664

Also, my experience suggests that emphatic claims like "no one" and "everyone" are never true. Different countries, different traditions, different schools, and different disciplines see to that. For example, MathWorld uses Grassmann's name, the Springer Encyclopaedia of Mathematics uses both, and a Web search turns up well over ten thousand hits. Whereas if we look for '"Plücker coordinates" Grassmannian' (so we don't include the line coordinate uses), we get fewer hits.

We cannot ignore the practice to which you refer, but the proper resolution is to have a disambiguation notice at the top of the Plücker coordinates article pointing to the "Grassmann coordinates" article — which I would love to see written, and have never managed to get around to. Do I detect a volunteer? --KSmrq^T 20:19, 24 March 2007 (UTC)

I am very impressed by the wealth of historical references that you came up with! Seriously! Hodge and Pedoe is a standard reference for properties of Plücker coordinates, whatever the name. On the other hand, and here I can speak very authoritatively, (1) you are mistaken that only

few modern authors would take much interest in exploring these coordinates for their own sake.

Au contraire, this is a very active area of research, especially in the context of the theory of standard monomials. I've read dozens of papers that use and explore, and refine, etc them.

(2) Moreover, I can't remember a single standard reference (past Hodge and Pedoe) that speaks of Grassmann coordinates (actually, I can't exactly remember Hodge-Pedoe either; it's been a while ). It's always Plücker embedding; whenever the term coordinates is used, it's Plücker coordinates. Here is a quick rundown:

• Goodman-Wallach Representations and Invariants of the Classical Groups
• Fulton-Harris Representation Theory, First Course
• Billey-Lakshmibai Singular loci of Schubert varieties
• Miller-Sturmfels Combinatorial commutative algebra
• Mumford Algebraic geometry I
• Weyman Cohomology of vector bundles and syzygies
• Shafarevich Basic algebraic geometry
• Griffiths-Harris
• Procesi Lie groups
• Fulton Young tableaux

This is just a random sample within my eyesight at the moment, and as it represents algebraic geometry, commutative algebra, representation theory and combinatorics, it's fairly exhaustive. Just so you don't think I'm biasing the data, there were TWO books where I didn't find see Plücker embedding/coordinates (under any name): Hartshorne (a well known fact), and Fulton Intersection theory (not sure if it's there, maybe, it's too down-to-earth for his purposes; he uses Schubert classes extensively).

(3) Just to be sure, I ran a MathSciNet search and discovered something else: all or nearly all hundreds if not thousands of papers that mention Grassmann coordinates mean something else, namely odd coordinates in the context of supersymmetry. So actually, it's worse that I had thought, because not only is the name Grassman coordinates for, well, Plücker coordinates is obsolete, but actually the name has been expropriated to mean something else.

(4) In general, I would put very little trust in what Wolfram and Ko are writing about mathematics, and if they flatly contradict my professional knowledge, so much the worse for them!

Anyway, gotta go, but I hope that I gave you enough references! Maybe the history was not fair to Grassmann, but mathematics terminology is neither accurate in this regard, nor frozen in time. Arcfrk 21:36, 24 March 2007 (UTC)

(This reply was written after the one below.) I have been pleasantly surprised at the volume of historical mathematics making its way to the Web. And thanks for your references.

I suspect, however, that all is not quite as you represent it. For example, I checked Fulton & Harris, Representation Theory, and found no mention of Plücker coordinates. (Do you have a page number?) I used Amazon.com's facilities and found a mention of Plücker coordinates in Shafarevich & Reid, and will assume they use the generalized form; likewise I confirmed Billey & Lakshmibai. It may take some time to check the other books, if possible. Yes, I am aware of no disagreement about the Plücker embedding, the Plücker relations, and other such; but I specifically distinguish the Plücker coordinates.

As for the physics use, we already have an article on "Grassmann number" that we can point to in a disambiguation. Clearly, this skews naive hit statistics.

Like you, I have limited confidence in MathWorld; but the Springer Encyclopedia still stands. My point is that you overstate your case when you claim universality.

Of course, I am aware of the phenomenon that mathematical inventions (and others) are often named for someone other than their true inventor. But there really is no need to inflict that on Grassmann, especially with Hodge & Pedoe as a solid source. (I have found one interesting variant, which is Plücker–Grassmann coordinates.) I simply cannot accept your proposal, in part because it is flatly wrong; the true Plücker coordinates apply only to lines in three-dimensional space, not arbitrary linear subspaces of a three-dimensional vector space. (Not surprising, given his seminal work on line geometry.) Instead of "Grassmann coordinates" one could use "generalized Plücker coordinates", but I think a simple disambiguation notice at Plücker coordinates is preferable.

But here's a consideration: We are debating the title of an article that does not exist. Are you planning to write something in the near future? --KSmrq^T 23:18, 24 March 2007 (UTC)

Please, re-reread (2) above: I said that no one uses Grassmann coordinates, if the term coordinates is used at all (which is not the case with Fulton and Harris, but is the case with most algebraic geometry books and all standard monomial literature) then it is Plücker coordinates. I have no vested interest in arguing, and don't have any more time to spare, just letting you know what professionals in the field think. You are free to believe what you want. If you are really bent on verifying, you can find Miller and Sturmfels on the web; p.273 ff. Also Fulton p.132, and check Procesi, I only have an old version here, page numbers don't match. Don't forget to apologize when you are done confirming. Arcfrk 00:51, 25 March 2007 (UTC)

I have to say that 'Grassmann coordinates' holds no appeal for me as terminology. It would be better to have some good history, but to use 'Plücker coordinates' everywhere, IMO. Charles Matthews 21:05, 24 March 2007 (UTC)

I understand these things are like Mom's cooking, even if everyone's Mom is different.

But in this case it appears likely that more than half of our readers would expect "Grassmann". Combine that with venerable attested mathematical usage and the true history of the idea, throw in the awkwardness of Arcfrk's "Plücker coordinates (three dimensions)" proposal and the simplicity of a disambiguation notice, and cap it off with the mathematical maturity of the readers who know about Grassmannians, and the choice is clear. Somebody is going to be uncomfortable no matter what, so we really ought to give Grassmann his due.

And speaking of choices, I've seen at least four different notations for a Grassmannian, which a reader would never suspect from our article! These include: G(k,V) — or G(k,n) as short for G(k,Cⁿ), Gr(n,k), G_k,n — or G_k(V), and Grass_kV, along with other reversals of k and n, and different choices of typeface. Fortunately, we don't have to decide this in the title of the article; but it would be nice to mention the alternatives in the body. --KSmrq^T 22:12, 24 March 2007 (UTC)

I was surprised to find two of the editors I most often agree with disagreeing with each other. And of course, I agree with you both :). I agree with Arcfrk that Plücker coordinates is the most common term in modern usage (in differential geometry too, although here the grassmannian is most definitely a manifold and not a variety :) ). But I also agree with KSmrq that this was not always the case and is historically inaccurate. Unfortunately, though, after the typical mathematician has been sloppy, lazy and historically inaccurate for a couple of generations, and a few text books have been written and read, usage changes: note that the citations supporting Grassmann coordinates tend to come from the earlier part of the last century, while Plücker coordinates are more likely to be supported by references from the later part. There so many misattributions of mathematical concepts in the literature that it can be a running joke with lecturers, e.g., "The Klein quadric (so named because it was discovered by Plücker)..."

May I suggest a way forward? I would suggest that the article that really needs to be written is Plücker embedding, which currently redirects. Grassmann/Plücker coordinates could be discussed here, with reference to both terminologies, and Grassmannian could be updated to reflect the new information. And thanks to the research done here, the new article will surely be well-sourced!

As for terminology, let me add Gr_k(V) and Gr_k(n) to the list, together with the fact that k-n notations sometimes denote the real grassmannians! Geometry guy 18:19, 27 March 2007 (UTC)

At least Klein was Plücker's student. Poor Grassmann regularly gets short shrift, partly because his writing and advanced ideas were so hard to understand. And yes, I'm aware of Stigler's law of eponymy. :-)

I think we'll get this sorted out; it's not that uncommon a situation. In fact, as I write, a helpful recollection comes to mind: I have sometimes used the more explicit phrase "Plücker line coordinates". If I can't convince Charles Matthews and Arcfrk to do the right and honorable thing, to give Grassmann his coordinates, then at least I have an acceptable name under which to deposit the existing article. I'm sure Charles understands, though Arcfrk may not, that we cannot always find names that keep everyone happy, because we do not have the luxury of forcing consistency on the world, not even the mathematical world.

But until someone is prepared to write the article, debating its name is pointless. I have always meant to, but I found the task of converting Hodge and Pedoe into language and examples accessible to the thousands of readers who really do need line coordinates, well, exhausting.

I have noticed a phenomenon, and read supporting literature, than seems to escape many writers. (A recent example can be found on the mathematics reference desk.) Often readers will understand a concrete example much more easily than an abstract formula. And I mean extremely concrete, such as using specific numbers. Is this dumb? I don't think so. Richard Feynman, widely considered a very bright guy, said he routinely constructed such examples in his head as people around him discussed things in the abstract; then from his example he could generate relevant and focused questions that often surprised the expositors. So I like to include such examples in my writing. Yes, it's extra work. Yes, some folks turn up their noses. I can live with that.

Back to the topic at hand: Thanks for the Plücker embedding suggestion, and for the additional variations on Grassmannian notation. (And is "Grassmannian" capitalized? Hmm, another variation.) I remember using the general coordinates themselves in my graduate school days (more recent than the first half of the last century!), but I'm not sure I'm curious enough to try to find my course notes to see what name was used at the time. (I think it was still Grassmann coordinates, but I don't trust my memory.) --KSmrq^T 20:41, 27 March 2007 (UTC)

I'm a big fan of Grassmann (he's up there with Weyl and Cartan in my book): he was ahead of his time. In my opinion he discovered Clifford algebras before Clifford did (although I am a big fan of Clifford too). Anyway, I'm impressed by your flexible response and am sure this circle of ideas will turn out nicely in the end. I think it is worth making a stub for Plücker embedding, even if we don't have the time to do more just yet: I'm willing to give it a shot. As for "grassmannian", the decapitalization of derived adjectives would be automatic at the French wiki, but is desperately inconsistent in English, where abelian is rarely capitalized, but Euclidean nearly always is. I work in an international world and write mathematics in international English, so I adopt nearly the only logical convention there is: Grassmann coordinates, but grassmannian manifold. Of course, I wouldn't dream to impose this convention on wikipedia ;-) Geometry guy 21:31, 27 March 2007 (UTC)

(Okay you could also capitalize every word derived from a proper name.) Geometry guy 21:35, 27 March 2007 (UTC)

As it happens, I am a big fan of Grassmann, too (and yes, Grassmann did consider Clifford algebras, even though the current mathematical usage doesn't reflect it, and was one of the founders of noncommutative algebra). Incidentally, it was Plücker who introduced homogeneous coordinates into projective geometry, which may or may not be the reason why many coordinates are named after him. This should be expounded nicely in Klein's "Lectures on the development of mathematics in XIX century", which I don't have at the moment. On the other hand, Grassmann does get a lot of recognition that he may not have fully deserved: all those physics papers mentioning "Grassmann variables" in the context of supersymmetry. Arcfrk 03:45, 28 March 2007 (UTC)

Usually homogeneous coordinates are credited to Möbius, as in this MacTutor biography.

As for naming, I'm guessing a "contamination" process applies for both the mathematicians and the physicists.

• For the physicists, Grassmann's name is connected with wedge products, and rightly so, through exterior algebra — which is to say, Grassmann algebra. The wedge product is alternating: x∧x = 0. These handy new coordinates the physicists need are also alternating (like perpendicular vectors in a Clifford algebra). Hmm, what shall we call them? "Grassmann numbers" is memorable. And since these are used as coordinates, soon "Grassmann coordinates" emerge. Which would be less likely if they knew of the prior use; but that's wishful thinking.
• For the mathematicians, Plücker's name is connected with various nearby things. We have to be careful to avoid "Plücker numbers" and "Plücker formulae", used in the theory of curves. But the Plücker map/embedding is dangerously relevant, as is "Plücker relations". And we already have Plücker coordinates used in a special case. Mathematicians are supposed to generalize, are they not? Apparently the combination of temptation and ignorance was too much in this case as well.

Were we writing a textbook, we could choose our own definitions and lecture the reader on why no other choice is logical. Instead, we are writing an encyclopedia, and must document the facts as we find them. And the fact is, confusion and inconsistency are rampant. Shocking as it may be to discover that this disease infects mathematicians, the evidence surrounds us. So, we do the best we can to document the mess and help guide the reader through it.

In my view, we would best serve both the physicists and the modern algebraic geometers by giving Grassmann coordinates their rightful name. My arguments are:

• The name properly reflects the history of invention.
• Before the younger generation of mathematicians forgot, the name was standard.
• Our best sources actually describing these coordinates (as opposed to applying them) use the name.
• The name avoids confusion with the unrelated Plücker numbers.

But that's a preference, not a religious position. We can cope with international spelling variations, and I'm sure we can cope with this, too. Meanwhile, I encourage Geometry guy to continue work on Plücker embedding. --KSmrq^T 17:03, 28 March 2007 (UTC)

[edit] the alhambra

hi mate, how's it going. I will be at the Alhambra in about a week. I hear they have a lot of nice wallpaper groups. If so, I'll take a bunch of photos and dump them on a server for you. Dmharvey 18:42, 27 March 2007 (UTC)

Sounds delightful; a conference? As you may recall, there has been some question about whether all 17 groups are in evidence. (Here are photographs of 13, but with no locations given.) At one time it was thought that p2, pgg, pg, and p3m1 were missing, but Pérez-Gómez (“The four regular mosaics missing in The Alhambra”) claims to have found these. A review of his images by Coxeter leaves p3m1 in doubt. Photograph it and find everlasting fame!

Speaking of fame, I understand that Elkies contributed a helpful suggestion to the recent E₈ calculation; how do folks in the department rate this news? Earthshaking? Ho-hum? Huh, what news?

I assume your wikibreak is correlated with grad school. Are you done with coursework? Buried deep in thesis research? Do you get quality time with Mazur? Is he a hands-on advisor or does he tend to leave you on your own?

Great to hear from you. (I keep lobbying for blahtex; we'll have STIX Fonts Real Soon Now.) --KSmrq^T 19:46, 27 March 2007 (UTC)