Maximal invariable update operator based on splitting

Abstract

There are a very large number of beliefs in an agent generally. Now many researchers think that efficient belief revision should be performed only in the part of its relevant states at a time. So Parikh proposed relevance criterion and showed that AGM belief change operations do not always satisfy it. By introducing the notion of maximal invariable partial meet contraction into AGM model, we obtain a class of partial meet contractions that satisfy Parikh's relevance criterion. It benefits computing an update operator by a local update one. Together with the notion of essential letter, an open problem which proposed by Makinson was resolved. © 2008 Springer-Verlag Berlin Heidelberg.