Knowledge-level analysis of belief base operations

摘要

Recent developments in philosophical studies of belief revision have led to the construction of models that are much closer to actual computing systems than the earlier models. An operation of contraction (revision) on a logically closed belief set can be obtained by assigning to it a finite belief base and an operation of contraction (revision) on that base. Exact characterizations of such base-generated operations have been o btained. In this way, computational tractability and other realistic properties of operations on finite bases can be combined with a precise analysis that is independent of the symbolic representation.