Abductive Framework for Nonmonotonic Theory Change

Abstract

This paper proposes a method of nonmonotonic theory change. We first introduce a new form of abduction that can account for observations in nonmonotonic situation. Then we provide a framework of autoepistemic update, which describes nonmonotonic theory change through the extended abductive framework. The proposed update semantics is fairly general and provides a unified framework for various update semantics such as first-order update, view update of databases, and contradiction removal of nonmonotonic theories. 1 Introduction A lot of theories for belief change have been proposed in AI and related fields. At abstract and philosophical levels, the belief dynamics have been studied as rationality postulates to be satisfied by belief sets (e.g., [ Alchour'ron et al., 1985; Katsuno and Mendelzon, 1991b ] ). In the field of AI and databases, various researchers have proposed revision, contraction, and update methods of data and knowledge bases. On the AI side, revision and update method...