Proof methods for reasoning about possibility and necessity

AbstractPossibilistic logic is a quantitative method for uncertainty reasoning that is closely related to Zadeh's fuzzy set theory. In this paper, we formulate it as a kind of multimodal logic and develop some proof methods for it, including tableau method and two styles of natural deduction methods. The completeness and soundness of these methods are proved. Finally, some potential applications and the possible research directions are pointed out