Contradiction Removal Semantics with Explicit Negation
نویسندگان
چکیده
Well Founded Semantics for logic programs extended with eXplicit negation (WFSX) is characterized by that, in any model, whenever :a (the explicit negation of a) holds, then a (the negation by default of a) also holds. When explicit negation is used contradiction may be present (e.g. a and :a both hold for some a) and thus no semantics is given to the program. We introduce here the notion of removing some contradictions, through identifying the set of models obtained by revising closed world assumptions. One such unique model is singled out as the contradiction free semantics (CRSX). When contradiction does not arise, the contradiction removal semantics coincides with WFSX.
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