A Knowledge Representation Framework Based on Epistemic Logic

We introduce a uniform non-monotonic framework for knowledge representation based on epistemic logic which is sufficiently general to encompass several non-monotonic formalisms, including circumscription, autoepistemic logic, various semantics proposed for logic programs and deductive databases (stable semantics, well-founded semantics and stationary semantics) as well as Gelfond's epistemic specifications. The existence of such a uniform framework allows us not only to provide simpler and perhaps more natural definitions of various formalisms but it also enables us to better understand mutual relationships existing between them. Keywords: Non-monotonic reasoning, semantics of logic programs, disjunctive logic programs and deductive databases. 1 Introduction In recent years, various approaches to non-monotonic reasoning and different semantics for normal and disjunctive logic programs have been proposed, including: ffl Autoepistemic Logic [Moo85]; ffl Circumscription, CWA, GCWA, EC...