A new measure of entropy and its connection with a similarity measure for intuitionistic fuzzy sets

We propose a new measure of entropy for intuitionistic fuzzy sets. This paper is in a sense a continuation of our previous paper on entropy of intuitionistic fuzzy sets — the inferences are based on the same two types of distances as previously — to the farer and to the nearer crisp elements. But now we propose the formulas easier to calculate. Next, we show that the same result can be obtained when the distance between the element considered and its complement is taken into account. The proposed entropy measure is closely related to the similarity measure we have proposed earlier. We also suggest π-entropy, a function strongly accounting for the lack of knowledge as to the membership and non-membership.