generalized notion of) choice structure in terms of belief revision by adding: (1) the possibility that an item of ''information …'' might be discarded as not credible (thus dropping the AGM success axiom) and (2) the possibility that an item of information …, while not accepted as fully credible, may still be ''taken seriously'' (we call such items of information ''allowable''). We …

We provide a new characterization of AGM belief revision in terms of a Kripke-Stalnaker-Lewis semantics. We consider …

We provide a new characterization of both belief update and belief revision in terms of a Kripke-Lewis semantics. We …