Knowledge Base Revision Using Circumscription

In this paper we present a framework of retrospective reasoning to deal with the belief revision problem in knowledge systems. First, a first-order knowledge base is represented by a set of formulas in a first order epistemic belief language that contains objective formulas as well as belief formulas. Secondly, we define the revision operation by applying a form of prioritized circumscription to this representation of the knowledge base. The retrospective ability is achieved by maintaining the evolutional information of a knowledge system. We compare our approach with previously proposed methods and show this ability is important to belief revision. In particular, we show that the revision semantics defined in this way satisfies the AGM postulates that are reformulated in our belief language. 1 Introduction A knowledge base should be updated as our perception of the world described by it changes. Revision is the most common type of updates: it adds newly acquired knowledge to the syst..