Distance semantics for belief revision

Abstract

Abstract A vast and interesting family of natural semantics lor belief revision is defined. Suppose one is given a distance d between any two models. One may then define the revision of a theory K by a formula α as the theory defined by the set of all those models of α that are closest, by d . to the set of models of K . This family is characterized by a set of rationality postulates that extends the AGM postulates. The new postulates describe properties of iterated revisions.