Description Logic Based Ontology Languages

Ian Horrocks: Description Logics (DLs) are a family of class based knowledge representation formalisms characterised by the use of various constructors to build complex classes from simpler ones, and by an emphasis on the provision of sound, complete and (empirically) tractable reasoning services. Although they have a range of applications (e.g., configuration and information integration), they are perhaps best known as the basis for widely used ontology languages such as OWL. The decision to base OWL on DLs was motivated by a requirement that key inference problems be decidable, and that it should be possible to provide "practical" reasoning services to support ontology design and deployment. This talk will introduce description logics and their relationship to OWL, and then describe some of the algorithms and implementation techniques that have enabled them to satisfy this requirement in spite of the discouraging worst case complexity of the relevant decision problems.