Towards Defeasible Mappings for Tractable Description Logics

Abstract

We present a novel approach to denote mappings between EL-based ontologies which are defeasible in the sense that such a mapping only applies to individuals if this does not cause an inconsistency. This provides the advantage of handling exceptions automatically and thereby avoiding logical inconsistencies that may be caused due to the traditional type of mappings. We consider the case where mappings from many possibly heterogeneous ontologies are one-way links towards an overarching ontology. Questions can then be asked in terms of the concepts in the overarching ontology. We provide the formal semantics for the defeasible mappings and show that reasoning under such a setting is decidable even when the defeasible axioms apply to unknowns. Furthermore, we show that this semantics actually is strongly related to the idea of answer sets for logic programs