(delta, star)-equality of fuzzy sets
The Cai delta-equality of fuzzy sets corresponds to the Lukasiewicz t-norm. In this paper we study the notion of (star, delta)-equality, a concept which generalizes the delta-equality to the case of the fuzzy set theory based on an arbitrary continuous t-norm star. We investigate the robustness of some fuzzy implication operators in terms of (star, delta)-equality.
(delta, star)-equality fuzzy implication operators fuzzy relations