RACER system
From Wikipedia, the free encyclopedia
The RACER system (Renamed ABox and Concept Expression Reasoner) is a knowledge representation system that implements a highly optimized tableau calculus for a very expressive description logic (DL). It offers reasoning services for multiple TBoxes and ABoxes (as defined in DL). The system implements the DL 
(see ALCQHI) also known as 
(see SHIQ). This is the basic logic 
(see ALC (logic)) augmented with qualifying number restrictions, role hierarchies, inverse roles, and transitive roles. In addition to these basic features, RACER also provides facilities for algebraic reasoning including concrete domains for dealing with:
- min/max restrictions over the integers,
- linear polynomial (in-)equations over the reals or cardinals with order relations,
- nonlinear multivariate polynomial (in-)equations over complex numbers,
- equalities and inequalities of strings.
RACER supports the specification of general terminological axioms. A TBox may contain general concept inclusions (GCIs), which state the subsumption relation between two concept terms. Multiple definitions or even cyclic definitions of concepts can be handled by RACER.
RACER implements the HTTP-based quasi-standard DIG for interconnecting DL systems with interfaces and applications using an XML-based protocol. RACER also implements most of the functions specified in the older Knowledge Representation System Specification (KRSS).
The RACER system has been initially developed by researchers of the University of Hamburg. The authors now work at the Hamburg University of Technology, Germany, and Concordia University, Canada.
Since the summer of 2005 the system is developed, maintained and supported by Racer Systems, a Hamburg, Germany based company. To indicate the advantages of the commercial version the product is now called RacerPro.
RacerPro is available on a wide variety of computing platforms with a selection of license options for single users, client-server applications or for use at a campus/site. Prices start at about thousand Euro. For individuals working at a university or school an academic but time-limited license (180 days) is available for free. Students can get a free license of the RacerPro system for their diploma or Ph.D. thesis.
