Belief Revision
Abstract
This chapter gives an introduction to the problem of rational belief change and its formal modeling in qualitative logical theories. It first presents an outline of the approach based on rationality postulates and of the most important constructive approaches within the classical AGM model of belief revision. Then it gives the basic ideas of extensions of the classical model to iterated belief revision, to multiple revision and to two-dimensional belief change, to belief merging and to belief updates, as well as to default reasoning.