A Protégé Plug-in for Defeasible Reasoning

International audienceWe discuss two approaches for defeasible reasoning in DescriptionLogics that allow for the statement of defeasible subsumptions of the form “αsubsumed by β usually holds”. These approaches are known as prototypical rea-soning and presumptive reasoning and are both rooted in the notion of RationalClosure developed by Lehmann and Magidor for the propositional case. Herewe recast their definitions in a defeasible DL context and define algorithms forprototypical and presumptive reasoning in defeasible DL knowledge bases. Inparticular, we present a plug-in for the Prot ́eg ́e ontology editor which imple-ments these algorithms for OWL ontologies. The plug-in is called RaMP andallows the modeller to indicate defeasible information in OWL ontologies andcheck entailment of defeasible subsumptions from defeasible knowledge base