RACER is a knowledge representation system it supports:
* the DIG standard such that, for instance, graphical ontology editors such as OilEd can be usedwith RACER as a reasoning engine.
* directly read knowledge bases specified w.r.t.the DAML+OIL,RDFS or RDF standard (although there are some restrictions on some DAML+OIL language expressions).
* an interactive graphical shell called RICE.
This came in response to a question on the RDF-Interest mailing list about inferencing tools the other ones mentioned were: