Postulates for Conditional Belief Revision

In this paper, we present a scheme of postulates for revising epistemic states by condit ional beliefs. These postulates are supported mainly by fol lowing the specific, non-classical nature of conditionals, and the aim of preserving condi t ional beliefs is achieved by studying specific interactions between conditionals, represented properly by two relations. Because one of the postulates claims propositional belief revision to be a special case of condit ional belief revision, our framework also covers the work of Darwiche and Pearl [Darwiche and Pearl, 1997], and we show that all postulates presented there may be derived from our postulates. We state representation theorems for the principal postulates, and finally, we present a condit ional belief operator obeying all of the postulates by using ordinal condit ional functions as representations of epistemic states.