• Kyungpook Mathematical Journal
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• 제59권1호
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• pp.163-174
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• 2019

The object of this paper is to classify paracontact metric ($k,{\mu}$)-spaces satisfying certain curvature conditions. We show that a paracontact metric ($k,{\mu}$)-space is Ricci semisymmetric if and only if the metric is Einstein, provided k < -1. Also we prove that a paracontact metric ($k,{\mu}$)-space is ${\phi}$-Ricci symmetric if and only if the metric is Einstein, provided $k{\neq}0$, -1. Moreover, we show that in a paracontact metric ($k,{\mu}$)-space with k < -1, a second order symmetric parallel tensor is a constant multiple of the associated metric tensor. Several consequences of these results are discussed.

• Journal of applied mathematics & informatics
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• 제35권3_4호
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• pp.323-330
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• 2017

Recently Samet, Vetro and Vetro introduced the notion of ${\alpha}$-${\Psi}$-contractive type mappings and initiated some fixed point theorems in complete metric spaces. The notion of ${\alpha}_*$ - ${\Psi}$-contractive multifunctions and initiated some fixed point results by Hasanzade Asl et. al. [8]. In this paper, we introduced the notion of ${\alpha}_*$ - ${\Psi}$-contractive multifunctions in a fuzzy metric space and gave fixed point results for these multifunctions in complete fuzzy metric spaces. We also obtain a fixed point results for self-maps in complete fuzzy metric spaces satisfying contractive condition.

• Journal of applied mathematics & informatics
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• 제16권1_2호
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• pp.371-381
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• 2004

In this paper, fuzzy metric spaces are redefined, different from the previous ones in the way that fuzzy scalars instead of fuzzy numbers or real numbers are used to define fuzzy metric. It is proved that every ordinary metric space can induce a fuzzy metric space that is complete whenever the original one does. We also prove that the fuzzy topology induced by fuzzy metric spaces defined in this paper is consistent with the given one. The results provide some foundations for the research on fuzzy optimization and pattern recognition.

• 대한수학회논문집
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• 제23권3호
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• pp.427-446
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• 2008

In this paper, we give some new definitions of compatible mappings in intuitionistic fuzzy metric spaces and we prove a common fixed point theorem for four mappings under the condition of compatible mappings of type (I) and of type (II) in complete intuitionistic fuzzy metric spaces.

• Kyungpook Mathematical Journal
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• 제54권1호
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• pp.113-122
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• 2014

In this paper, we introduce S-metric spaces and give their some properties. Also we present a common fixed point theorem for multivalued maps on complete S-metric spaces. The single valued case and an illustrative example are given.

• Journal of applied mathematics & informatics
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• 제29권3_4호
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• pp.1027-1035
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• 2011

In this paper, we introduce the concept of generalized weak q-contractivity for multivalued maps defined on quasi-metric spaces. A new fixed point theorem for these maps is established. The convergene of iterate schem of the form $x_n+1\;{\in}\;Fx_n$ is investigated. And a new periodic point theorem for weakly q-contractive self maps of quasi-metric spaces is proved.

• 대한수학회논문집
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• 제22권4호
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• pp.513-526
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• 2007

In this paper, we give some new definitions of M-fuzzy metric spaces and we prove a common fixed point theorem for six mappings under the condition of compatible mappings of first or second type in two complete M-fuzzy metric spaces.

• Kyungpook Mathematical Journal
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• 제54권3호
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• pp.485-500
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• 2014

In this paper, we establish coupled fixed point theorems for mixed monotone mappings satisfying nonlinear contraction involving a pair of altering distance functions in ordered G-metric spaces. Via presented theorems we extend and generalize the results of Harjani et al. [J. Harjani, B. L$\acute{o}$pez and K. Sadarangani, Fixed point theorems for mixed monotone operators and applications to integral equations, Nonlinear Anal. 74 (2011) 1749-1760] and Choudhury and Maity [B.S. Choudhury and P. Maity, Coupled fixed point results in generalized metric spaces. Math. Comput. Model. 54 (2011), 73-79].

• 대한수학회논문집
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• 제27권2호
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• pp.265-277
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• 2012

In this paper we establish two common fixed point theorems in fuzzy metric spaces. These theorems are generalisations of the Banach contraction mapping principle and the Kannan's fixed point theorem respectively in fuzzy metric spaces. Our result is also supported by examples.

• 대한수학회논문집
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• 제23권1호
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• pp.111-124
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• 2008

In this paper, we give some fixed point theorems on fuzzy metric spaces with an implicit relation. Our results extend and generalize some fixed point theorems on complete fuzzy metric spaces by using a new technique.