The main goal of this publication is to show that the basic constructions in theories fuzzy sets, soft hesitant sets or intuitionistic have a common background, based on theory monads categories. It proven ad hoc defined concepts individual theories, such as power set structures these relations approximation operators by are only special examples applications monad This makes it possible, one h...

Fuzzy best simultaneous approximation of a finite number of functions is considered. For this purpose, a fuzzy norm on $Cleft (X, Y right )$ and its fuzzy dual space and also the  set of subgradients of a fuzzy norm are introduced. Necessary case of a proved theorem about characterization of simultaneous approximation will be extended to the fuzzy case.

Hesitant fuzzy sets (HFSs), which were generalized from fuzzy sets, constrain the membership degree of an element to be a set of possible values between zero and one; furthermore if two or more decision-makers select the same value, it is only counted once. However, a situation where the evaluation value is repeated several times differs from one where the value appears only once. Multiset hesi...

The hesitant fuzzy linguistic term sets (HFLTSs), which can be used to represent an expert’s hesitant preferences when assessing a linguistic variable, increase the flexibility of eliciting and representing linguistic information. The HFLTSs have attracted a lot of attention recently due to their distinguished power and efficiency in representing uncertainty and vagueness within the process of ...

Abstract The hesitant fuzzy set has been an important tool to address problems of decision making. There are several various improved sets, such as dual set, interval-valued and intuitionistic however, no one kind sets could reflect attitude characteristics makers on time-sequences. In reality, time-sequence is sector situations might have different knowledges the same alternative at moments. T...

The aim of this manuscript is to introduce the \((\alpha,\beta)\)-hesitant fuzzy set and apply it semigroups. In paper, as a generalization concept hesitant sets semigroup theory, subsemigroups semigroups introduced, related properties are discussed. Furthermore, we define study ideals on particular, investigate structure ideal generated by in semigroup. addition, also concepts semiprime semigr...

Moreover, Zhu et al. [11], developed dual hesitant fuzzy sets (DHFSs) as a new extension of HFSs. The DHFS is a comprehensive set encompassing several existing fuzzy sets with certain conditions, whose membership and nonmembership are represented by a set of possible values respectively. In particular cases, DHFSs can reduce to some existing fuzzy sets, such as FSs, IFSs, HFSs and FMSs. From a ...