(inf, sup)-Hesitant Fuzzy Ideals of BCK/BCI-Algebras

Abstract

In this paper, we introduce the concept of (inf, sup)-hesitant fuzzy ideals, which is a generalization of the concept of interval-valued fuzzy ideals, in BCK/BCI-algebras and its related properties are investigated. The concept is established in terms of sets, fuzzy sets, negative fuzzy sets, interval-valued fuzzy sets, Pythagorean fuzzy sets, bipolar fuzzy sets and hesitant fuzzy sets. Moreover, characterizations of ideals, fuzzy ideals, anti-fuzzy ideals, negative fuzzy ideals, Pythagorean fuzzy ideals and bipolar fuzzy ideals of BCK/BCI-algebras are discussed in terms of (inf, sup)-hesitant fuzzy ideals and interval-valued fuzzy ideals.