Fuzzy logic in the narrow sense is symbolic logic with a comparative notion of truth developed fully in the
spirit of classical logic (syntax, semantics, axiomatization, truth-preserving deduction, completeness, etc.; both
propositional and predicate logic). It is a branch of many-valued logic based on the paradigm of inference
under vagueness. This fuzzy logic is a relatively young discipline, both serving as a foundation for the fuzzy
logic in a broad sense and of independent logical interest, since it turns out that strictly logical investigation
of this kind of logical calculi can go rather far.