Elsevier

Fuzzy Sets and Systems

Volume 403, 15 January 2021, Pages 139-147
Fuzzy Sets and Systems

Short communication
New results on the modularity condition for overlap and grouping functions

https://doi.org/10.1016/j.fss.2019.10.014Get rights and content

Abstract

Recently, Wang and Liu investigated the modularity condition for overlap and grouping functions [Fuzzy Sets Syst. 372 (2019) 97-110]. They characterized the modularity equation between overlap (grouping) functions and proper uninorms, which belong to the most studied classes. In this paper, as a supplement of the above paper, we explore some new results on the modularity condition for overlap (grouping) functions and uninorms.

Section snippets

A brief review of overlap and grouping functions

In recently years, as two kinds of not necessarily associative fuzzy logic connectives, overlap functions [4] and grouping functions [5] were introduced by Bustince et al. in 2009 and 2012, respectively. Those two concepts originated from some problems in image processing, classification and decision making. In addition, in the past few years, overlap and grouping functions have been a rapid development both in theory and applications.

In theory, there exist many discussions involving various

Preliminaries

In this section, we briefly introduce some basic concepts and definitions related to t-norms, t-conorms, overlap (grouping) functions and uninorms, which shall be needed in the sequel.

Definition 2.1

[25] A bivariate function T:[0,1]2[0,1] is said to be a t-norm if, for all x,y,z[0,1], it satisfies the following conditions:

(T1) Commutativity: T(x,y)=T(y,x);

(T2) Associativity: T(T(x,y),z)=T(x,T(y,z));

(T3) Monotonicity: T(x,y)T(x,z) whenever yz;

(T4) Boundary condition: T(x,1)=x.

Definition 2.2

[25] A bivariate function S:[0,

The new results

In this section, we explore some new results on the modularity condition for overlap functions over uninorms when the uninorms are disjunctive or conjunctive and locally internal on the boundary, and the modularity condition for uninorms over grouping functions when the uninorms are conjunctive or disjunctive and locally internal on the boundary. We presuppose that neutral element e(0,1) because the modularity condition between overlap (grouping) functions and t-norms (t-conorms) has been

Conclusions

In this paper, we explore some new results on the modularity condition for overlap (grouping) functions and uninorms. This work is a further investigation on the topic of modularity condition among specific binary aggregation functions and we mainly investigate Eq. (1) when the uninorms are disjunctive or conjunctive and locally internal on the boundary, and Eq. (2) when the uninorms are conjunctive or disjunctive and locally internal on the boundary. The results we obtained are complete and

Acknowledgements

The authors would like to express their sincere thanks to the Editors and anonymous reviewers for their most valuable comments and suggestions in improving this paper greatly. This work was supported in part by Higher Education Key Scientific Research Program Funded by Henan Province (No. 20A110011) and Research and Cultivation Fund Project of Anyang Normal University (No. AYNUKP-2018-B26).

References (46)

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