A Four-Valued Fuzzy Propositional Logic

It is generally accepted that knowledge based systems would be smarter and more robust if they can manage inconsistent, incomplete or imprecise knowledge. This paper is about a four-valued fuzzy propositional logic, which is the result of the combination of a four-valued logic and a fuzzy propositional logic. Besides the nice computational properties, the logic enables us also to deal both with inconsistency and imprecise predicates in a simple way.