• Journal of the Korean Institute of Intelligent Systems
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• v.3 no.1
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• pp.76-89
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• 1993

The evaluation of the Fuzzy Expected Value (FEV) as a typical value requires complete knowledge about the domain of the evaluation, and the distribution of the population in that domain [1]. Since in many situations it is not possible to gather complete knowledge regarding the domain, it is necessary to relax some of the restrictions involving the evaluation of FEV. In this paper we discuss solutions to this problem by using the concept of the Fuzzy Expected Interval (FEI).

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.1
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• pp.57-65
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• 2014

In this paper, we investigate the properties of L-lower approximation operators as a generalization of fuzzy rough set in complete residuated lattices. We study relations lower (upper, join meet, meet join) approximation operators and Alexandrov L-topologies. Moreover, we give their examples as approximation operators induced by various L-fuzzy relations.

• East Asian mathematical journal
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• v.27 no.3
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• pp.273-288
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• 2011

In this paper, we prove some common fixed point theorem for two nonlinear mappings in complete $\mathcal{M}$-fuzzy metric spaces. Our main results improved versions of several fixed point theorems in complete fuzz metric spaces.

• Korean Journal of Mathematics
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• v.29 no.1
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• pp.81-89
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• 2021

In this paper, we introduce the notions of a distance function, Alexandrov topology and ⊖-upper (⊕-lower) approximation operator based on complete co-residuated lattices. Under various relations, we define (⊕, ⊖)-fuzzy rough set on complete co-residuated lattices. Moreover, we study their properties and give their examples.

• Communications of the Korean Mathematical Society
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• v.23 no.4
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• pp.461-468
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• 2008

We define an $\epsilon$-fuzzy congruence, which is a weakened fuzzy congruence, find the $\epsilon$-fuzzy congruence generated by the union of two $\epsilon$-fuzzy congruences on a semigroup, and characterize the $\epsilon$-fuzzy congruences generated by fuzzy relations on semigroups. We also show that the collection of all $\epsilon$-fuzzy congruences on a semigroup is a complete lattice and that the collection of $\epsilon$-fuzzy congruences under some conditions is a modular lattice.

• Communications of the Korean Mathematical Society
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• v.19 no.1
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• pp.35-51
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• 2004

We introduce fuzzy closure systems and fuzzy closure operators as extensions of closure systems and closure operators. We study relationships between fuzzy closure systems and fuzzy closure spaces. In particular, two families F(S) and F(C) of fuzzy closure systems and fuzzy closure operators on X are complete lattice isomorphic.

• Korean Journal of Mathematics
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• v.20 no.2
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• pp.193-212
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• 2012

We investigate the properties of fuzzy connections. We find generating functions which induce fuzzy connections. In particular, we show that their connections relate to fuzzy relations.

• Journal of applied mathematics & informatics
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• v.37 no.5_6
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• pp.383-397
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• 2019

In this paper, we introduce ${\delta}$-fuzzy ideals in a pseudo complemented distributive lattice in terms of fuzzy filters. It is proved that the set of all ${\delta}$-fuzzy ideals forms a complete distributive lattice. The set of equivalent conditions are given for the class of all ${\delta}$-fuzzy ideals to be a sub-lattice of the fuzzy ideals of L. Moreover, ${\delta}$-fuzzy ideals are characterized in terms of fuzzy congruences.

• East Asian mathematical journal
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• v.18 no.2
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• pp.225-233
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• 2002

In this paper, we obtain the common fixed point for fuzzy mappings satisfying an implicit relation. We improve earlier results of this line.

• Journal of applied mathematics & informatics
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• v.19 no.1_2
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• pp.485-492
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• 2005

In this paper, we obtain some common fixed point theorems for fuzzy mappings in complete metric linear spaces.