Hesitant fuzzy set and its types

Since the problems of everyday life are relative , so far various tools such as fuzzy sets, intuitive fuzzy sets, etc. have been expressed to express these ambiguities in mathematical modeling. In 2009, Torra introduced a new horizon for the discussion of hesitant fuzzy sets to discuss issues that are uncertain about decision making. In the course of his work, the quantitative and qualitative expansion of uncertain fuzzy sets is discussed. In this article, for the purpose of introducing more researchers to hesitant fuzzy sets, we review the types of hesitant fuzzy sets such as dual uncertain fuzzy sets, generalized hesitant fuzzy sets, and so on.