Document Type : Research Paper
Author
College of Mathematics and Statistics, Northwest Normal University, Lanzhou 730070, PR China
Abstract
Restricted equivalence function, as an effective tool for the theoretical research and practical applications of fuzzy sets and systems along with fuzzy logic, has been continuously considered by scholars since it was proposed. In particular, recently, Bustince, Campi'{o}n, De Miguel et al. (H. Bustince, M.J. Campi'{o}n, L. De Miguel, E. Indur'{a}in, Strong negations and restricted equivalence functions revisited: An analytical and topological approach, Fuzzy Sets and Systems (2021), https://doi.org/10.1016/j.fss.2021.10.013.) investigated it using analytical and topological approach and proposed an open problem to ask whether the binary function $F(x,y)=T(I(x,y),I(y,x))$ obtained from a t-norm $T$ and a fuzzy implication function $I$ is a restricted equivalence function or not. In this paper, we pay attention to this problem and give positive answer of it. Specifically, first, we consider the binary functions obtained from overlap functions and fuzzy implication functions by following the construction way of $F$ and get the necessary and sufficient condition that makes such obtained $F$ to be a restricted equivalence function. Second, we introduce the so-called $\heartsuit$-functions, which are binary functions on unit closed interval with few additional axioms and obtain the necessary and sufficient condition that ensures the binary function constructed via any non-decreasing $\heartsuit$-function and fuzzy implication function as the way of $F$ to be a restricted equivalence function. Finally, we give the necessary and sufficient condition that makes $F$ to be a restricted equivalence function.
Keywords
2333-2346.
the measures of similarity, Fuzzy Sets and Systems, 158(5) (2007), 495-51.
functions and normal EN -functions: Image thresholding invariant, Pattern Recognition Letters, 29(4) (2008), 525-536.
revisited: An analytical and topological approach, Fuzzy Sets and Systems, 441 (2022), 110-129.
restricted equivalence functions and similarity measures for type-2 fuzzy sets, IEEE Transactions on Fuzzy Systems, 30(9) (2022), 4005-4016.
limiting properties, Fuzzy Sets and Systems, 252 (2014), 39-54.
Sciences, 279 (2014), 1-17.
applied on clustering techniques, Proceedings of the Joint 2009, International Fuzzy Systems Association World
Congress and 2009, European Society of Fuzzy Logic and Technology Conference, Lisbon, Portugal, July 20-24, 2009 DBLP, (2009).
M. Reformat, W. Melek (eds.), Fuzzy Logic in Intelligent System Design, NAFIPS 2017, Advances in Intelligent
Systems and Computing, Springer, Cham, 648 (2018), 410-420.
extending latticevalued restricted equivalence functions used for constructing similarity measures on L-fuzzy sets,
Information Sciences, 441 (2018), 95-112.
Fuzzy Sets and Systems, 323 (2017), 19-55.
Systems, 132(1) (2002), 113-124.