Abstract

There are several ways to extend the classic logical connectives for fuzzy truth degrees in such a way that their behavior for the values 0 and 1 work exactly as in the classical one. For each fuzzy semantics the formulas which are always true can change. But these sets are always a subset of the classical tautologies. The fuzzy semantics whose tautologies are identical to the classical tautologies are called here by “classic-like fuzzy semantics”. In this paper we will prove that there are uncountable classes of classic-like fuzzy semantics and we will provide a characterization of them, i.e. we will determine a necessary and sufficient condition for a fuzzy semantic be classic-like. We also define a generic consequence semantic relation for fuzzy semantics and we will prove that for the classic-like fuzzy semantics, this notion coincides with the classical one