Sometimes Updates Are Circumscription

Abstract

Model-based revision of knowledge bases expressed as first-order theories was shown in [Winslett 88b] to be useful as a means of describing and reasoning about the effects of actions. This paper shows that model-based theory revision is actually expressible as a form of circumscription. This shows that in certain applications, the cumbersome conceptually machinery of circumscription can be replaced by the intuitively simpler ideas of model-based theory revision. Where theory revision techniques are insufficient to capture the semantics of change in an application, circumscription will offer a more flexible environment. In addition, future advances in computing circumscription can be mapped to improvements in computing theory revisions, and vice versa.