A protege plug-in for defeasible reasoning

Abstract

We discuss two approaches for defeasible reasoning in Description Logics that allow for the statement of defeasible subsumptions of the form “subsumed by usually holds”. These approaches are known as prototypical reasoning and presumptive reasoning and are both rooted in the notion of Rational Closure developed by Lehmann and Magidor for the propositional case. Here we recast their definitions in a defeasible DL context and define algorithms for prototypical and presumptive reasoning in defeasible DL knowledge bases. In particular, we present a plug-in for the Protege ontology editor which implements these algorithms for OWL ontologies. The plug-in is called RaMP and allows the modeller to indicate defeasible information in OWL ontologies and check entailment of defeasible subsumptions from defeasible knowledge bases.