Volker Haarslev and Ralf Möller
Practical description logic systems play an ever-growing role for knowledge representation and reasoning research even in distributed environments. In particular, the often-discussed semantic web initiative is based on description logics (DLs) and defines important challenges for current system implementations. Recently, several standards for representation languages have been proposed (RDF, OWL). By introducing optimization techniques for inference algorithms we demonstrate that sound and complete query engines for semantic web representation languages can be built for practically significant query classes. The paper introduces and evaluates optimization techniques for the instance retrieval problem w.r.t. the description logic SHIQ(Dn)-, which covers large parts of OWL. The paper discusses practical experiments with the description logic system Racer.