Triangular norms or t-norm, in short, and automorphisms are very useful to fuzzy logics in the narrow sense. Moreover, these notions are usually limited to the set [0,1]. In this paper we will consider a well known generalization of the t-norm for arbitrary bounded lattices and provide a generalization of automorphism notion for this same structure. We consider several typical lattice constructors and introduce versions of them for t-norms and morphisms. We also analyze some properties of these constructions.
The final goal of this study is to adapt the concept of fuzzy entropy of De Luca and Termini to deal with type-2 fuzzy sets. We denote this concept type-2 fuzzy entropy set. However, the construction of the notion of entropy measure on an infinite set, such us [0,1], is not effortless. For this reason, we first introduce the concept of quasi-entropy of a fuzzy set on the universe [0,1]. Furthermore, whenever the membership function of the considered fuzzy set in the universe [0,1] is continuous, we prove that the quasi-entropy of that set is a fuzzy entropy in the sense of De Luca and Termini. Finally, we present an illustrative example, where we use type-2 fuzzy entropy sets instead of fuzzy entropies in a classical fuzzy algorithm.
The aim of this work is to study a certain fuzzy implication, called (T, N)-implication, obtained by composition of a fuzzy negation and a t-norm. Thus, it discusses under which conditions such functions preserve the main properties of fuzzy implications, in which some are related to the laws of contraposition. Finally, we prove a result that ensure the necessary and sufficient conditions for a function I : [0,1] 2 → [0,1] to be a (T, N)-implication.