Revision on Stable Sets
Jiahong Guo · 2006
This article focuses on the revision of stable sets which are considered elegant representations for full belief states of fully-introspective agents. Two stages of change of a given stable set and new information are distinguished and some work has been done in respective stages: one is to do the revision work from the stable set to an intermediate theory, and the other is to expand the intermediate theory to get some new stable sets and then select the best one with the help of information value. Three different perspectives within AGM traditions for the revision work from a stable set to an intermediate theory have been put forward. Maximal S5 non-implying sets, sphere system and epistemic entrenchment orderings are employed in those three different approaches. The focus there is the contraction operator from stable sets (and new information) to intermediate theories. Some representation theorems between contraction operators and those three different systems are provided. Then the revision operator from stable sets to intermediate theories can be characterized with the help of contraction operators and a variant Levi-identity.