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Abstract : |
Abstract. We present a development of the theory of default information structures, combining ideas from domain theory with ideas from non-monotonic logic. Conceptually, our treatment is distinguished from standard default logic in that we view default structures as generating models rather than theories. Reiter's default rules are viewed as non-deterministic algorithms for generating preferred partial models. Using domain-theoretical notions, we improve the standard definition of extensions in default logic, by introducing the notion of dilation. We prove the existence of such dilations for a new, natural class of default information structures, properly including the so-called semi-normal ones. This class, called the class of rational structures, is a robust generalization of the usual kind of default rule system. Key words: domain theory, non-monotonic reasoning, default logic, sequent structures, information systems., |
