• Kyungpook Mathematical Journal
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• v.46 no.1
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• pp.119-130
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• 2006

A new class of functions is introduced in this paper. This class is called almost ${\delta}$-precontinuity. This type of functions is seen to be strictly weaker than almost precontinuity. By using ${\delta}$-preopen sets, many characterizations and properties of the said type of functions are investigated.

• The Pure and Applied Mathematics
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• v.17 no.3
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• pp.199-203
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• 2010

We introduce the notions of sg-semiopen set and other kinds of generalized sg-open sets and we investigate some properties for such generalized sg-open sets.

• Kyungpook Mathematical Journal
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• v.30 no.1
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• pp.87-93
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• 1990

• Honam Mathematical Journal
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• v.32 no.2
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• pp.307-331
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• 2010

The notion of intuitionistic fuzzy semi-pre interior (semi-pre closure) is introduced, and several related properties are investigated. Characterizations of an intuitionistic fuzzy regular open set, an intuitionistic fuzzy semi-open set and an intuitionistic fuzzy ${\gamma}$-open set are provided. A method to make an intuitionistic fuzzy regular open set (resp. intuitionistic fuzzy regular closed set) is established. A relation between an intuitionistic fuzzy ${\gamma}$-open set and an intuitionistic fuzzy semi-preopen set is considered. A condition for an intuitionistic fuzzy set to be an intuitionistic fuzzy ${\gamma}$-open set is discussed.

• Communications of the Korean Mathematical Society
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• v.26 no.1
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• pp.135-149
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• 2011

Using (r, s)-preopen sets [14] and pre-${\omega}_t$-closures [6], a new kind of covering property $P^t_{({\omega}_r,s)}$-closedness is introduced in a bitopological space and several characterizations via filter bases, nets and grills [30] along with various properties of such concept are investigated. Two new types of cluster sets, namely pre-(${\omega}_r$, s)t-${\theta}_f$-cluster sets and (r, s)t-${\theta}_f$-precluster sets of functions and multifunctions between two bitopological spaces are introduced. Several properties of pre-(${\omega}_r$, s)t-${\theta}_f$-cluster sets are investigated and using the degeneracy of such cluster sets, some new characterizations of some separation axioms in topological spaces or in bitopological spaces are obtained. A sufficient condition for $P^t_{({\omega}_r,s)}$-closedness has also been established in terms of pre-(${\omega}_r$, s)t-${\theta}_f$-cluster sets.

• Korean Journal of Mathematics
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• v.7 no.1
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• pp.117-121
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• 1999

In this paper, we introduce $m$-open(closed) mappings by $m$-sets, and obtain a number of their properties. In particular, $m$-open(closed) mappings are used to extend known results for ${\alpha}$-open mapping, semi-open mappings and preopen mappings.

• Bulletin of the Korean Mathematical Society
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• v.36 no.1
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• pp.91-108
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• 1999

In this paper, we introduce the notions of fuzzy ${\gamma}$-peropen (${\gamma}$-perclosed) sets and fuzzy ${\gamma}$-percontinuous (${\gamma}$-peropen, ${\gamma}$-perclosed) maps, and investigate some of their properties.

• Honam Mathematical Journal
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• v.32 no.1
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• pp.77-84
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• 2010

In this paper, we introduce the notion of almost minimal precontinuous function and investigate characterizations for such a function.

• Journal of the Chungcheong Mathematical Society
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• v.22 no.4
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• pp.667-673
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• 2009

In this paper, we introduce the notions of minimal precontinuity, m-preclosed graph, almost m-precompact and m-precompact and investigate some properties for such notions.

• Kyungpook Mathematical Journal
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• v.32 no.1
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• pp.21-30
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• 1992