Belief revision using possible and impossible worlds semantics

Real agents often have inconsistent beliefs. Yet, the AGM theory of belief change fails to model contradictory statements, without trivializing the belief set: the logic underlying the AGM model is classical and, thus, satisfies the explosion principle. Building on the work of Adam Grove, the present dissertation aims to provide a system of spheres that can allow the revision of inconsistent beliefs. The system of spheres will be constructed using the relevance logic B and will encompass both possible and impossible worlds.