The Complexity of Model Checking for Propositional Default Logics
2008
Abstract. Default logic is one of the most widely used formalisms to formalize commonsense reasoning. In this paper we analyze the complexity of deciding whether a propositional interpretation is a model of a default theory for some of the variants of default logic presented in the literature. We prove that all the analyzed variants have the same complexity and that this problem is in general Σ p 2 complete, while it is coNP complete under some restrictions on the form of the defaults. 1