Minimal Change and Maximal Coherence: A Basis for Belief Revision and Reasoning About Actions

Abstract

The study of belief revision and reasoning about actions have been two of the most active areas of research in AI. Both these areas involve reasoning about change. However very little work has been done in analyzing the principles common to both these areas. This paper presents a formal characterization of belief revision, based on the principles of minimal change and maximal coherence. This formal theory is then used to reason about actions. The resulting theory provides an elegant solution to the conceptual frame and ramification problems. It also facilitates reasoning in dynamic situations where the world changes during the execution of an action. The principles of minimal change and maximal coherence seem to unify belief revision and reasoning about actions and may form a fundamental core for reasoning about other dynamic processes that involve change. 1