ECAI 2004 Conference Paper

A unifying semantics for belief change

Richard Booth, Samir Chopra, Thomas Meyer, Aditya Ghose

Many belief change formalisms employ plausibility orderings over the set of possible worlds to determine how the beliefs of an agent ought to be modified after the receipt of a new epistemic input. While most such possible world semantics rely on a single ordering, we look at using an extra ordering to aid in guiding the process of belief change. We show that this provides a unifying semantics for a wide variety of belief change operators. By varying the conditions placed on the second ordering, different families of known belief change operators can be captured, including AGM belief contraction and revision, the severe withdrawal of Rott and Pagnucco, the systematic withdrawal of Meyer et. al, and the linear liberation and sigma liberation of Booth et al. This approach also identifies novel classes of belief change operators that are worth further investigation.

Keywords: Belief Revision, Possible Worlds Semantics, AGM contraction, withdrawal, liberation, AGM revision

Citation: Richard Booth, Samir Chopra, Thomas Meyer, Aditya Ghose: A unifying semantics for belief change. In R.López de Mántaras and L.Saitta (eds.): ECAI2004, Proceedings of the 16th European Conference on Artificial Intelligence, IOS Press, Amsterdam, 2004, pp.793-797.

ECAI-2004 is organised by the European Coordinating Committee for Artificial Intelligence (ECCAI) and hosted by the Universitat Politècnica de València on behalf of Asociación Española de Inteligencia Artificial (AEPIA) and Associació Catalana d'Intel-ligència Artificial (ACIA).