A reflection on fuzzy “complements”

A fuzzy set can be seen as a measure of the meaning of a predicate in a given universe. Generally, a predicate covers some elements of the universe and not others. In this paper the problem of determining the properties a fuzzy set should check to cover elements not covered by a predicate represented by a fuzzy set is reviewed. Thus the problems of determining the negation and antonym of a predicate and the possibility of finding a good measure to represent them are studied, and new concepts as the kernel of an antonymy are introduced.