• Journal of applied mathematics & informatics
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• v.42 no.1
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• pp.169-178
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• 2024

The purpose of this paper is to introduce the concept of pairwise fuzzy semi door spaces and study its properties and applications. The conditions for a pairwise fuzzy semi door space to become a pairwise fuzzy semi Volterra space and for a pairwise fuzzy semi Volterra space together with a pairwise fuzzy semi door space to become a pairwise fuzzy semi Baire space are established. Also, the inter-relations between pairwise fuzzy semi Volterra spaces and other fuzzy bitopological spaces such as pairwise fuzzy semi Baire space, pairwise fuzzy semi σ-Baire space, pairwise fuzzy semi D-Baire space, pairwise fuzzy semi GID-space, pairwise fuzzy semi door space are also discussed in this paper.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.10 no.2
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• pp.152-156
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• 2010

We define some terminologies on intuitionistic fuzzy metric space and prove that the topology generated by any intuitionistic fuzzy metric space is metrizable. Also, we show that if the intuitionistic fuzzy metric space is complete, then the generated topology is completely metrizable, a Baire space, and that an intuitionistic fuzzy metric space is precompact if and only if every sequence has a Cauchy subsequence.

• Kyungpook Mathematical Journal
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• v.55 no.1
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• pp.181-189
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• 2015

In this paper, we study Baire property of a family of spaces which contains properly the family of all topological spaces and generalize the existing results. Also, we study the images and inverse images of such spaces.

• Kyungpook Mathematical Journal
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• v.57 no.2
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• pp.199-210
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• 2017

In this paper, we analyze some new properties of nowhere dense and strongly nowhere dense sets. Also, we discuss the images of nowhere dense and strongly nowhere dense sets. Further, we study the properties of weak Baire space in generalized topological spaces.

• Journal of the Korean Mathematical Society
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• v.41 no.1
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• pp.21-38
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• 2004

We prove that a Banach space that is convex-transitive and such that for some element u in the unit sphere, and for every subspace Μ containing u, it happens that the subset of norm attaining functionals on Μ is second Baire category in $M^{*}$ is, in fact, almost-transitive and superreflexive. We also obtain a characterization of finite-dimensional spaces in terms of functions that attain their supremum: a Banach space is finite-dimensional if, for every equivalent norm, every rank-one operator attains its numerical radius. Finally, we describe the subset of norm attaining functionals on a space isomorphic to $\ell$$_1$, where the norm is the restriction of a Luxembourg norm on $L_1$. In fact, the subset of norm attaining functionals for this norm coincides with the subset of norm attaining functionals for the usual norm.m.

• Journal of the Korean Mathematical Society
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• v.54 no.2
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• pp.697-711
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• 2017

Let X, Y be real normed vector spaces. We exhibit all the solutions $f:X{\rightarrow}Y$ of the functional equation f(rx + sy) + rsf(x - y) = rf(x) + sf(y) for all $x,y{\in}X$, where r, s are nonzero real numbers satisfying r + s = 1. In particular, if Y is a Banach space, we investigate the Hyers-Ulam stability problem of the equation. We also investigate the Hyers-Ulam stability problem on a restricted domain of the following form ${\Omega}{\cap}\{(x,y){\in}X^2:{\parallel}x{\parallel}+{\parallel}y{\parallel}{\geq}d\}$, where ${\Omega}$ is a rotation of $H{\times}H{\subset}X^2$ and $H^c$ is of the first category. As a consequence, we obtain a measure zero Hyers-Ulam stability of the above equation when $f:\mathbb{R}{\rightarrow}Y$.