• Korean Journal of Mathematics
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• 제13권2호
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• pp.241-248
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• 2005

Some of the generalized continuous functions and their basic properties are introduced in concern with the cover theory. The open property of a function is a crucial tool for the survey of this area.

• 대한수학회보
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• 제51권2호
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• pp.437-442
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• 2014

In this paper we prove Ekeland's variational principle in the setting of locally complete spaces for lower semi continuous functions from above and bounded below. We use this theorem to prove Caristi's fixed point theorem in the same setting and also for lower semi continuous functions.

• Kyungpook Mathematical Journal
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• 제30권1호
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• pp.95-100
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• 1990

• 대한수학회보
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• 제39권4호
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• pp.535-541
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• 2002

In this paper, we introduce the concept of lower semi-continuous from above functions and show that many well-known results, such as Ekland's and Caristi's theorems, remain also true under lower semi-continuous from above functions.

• 충청수학회지
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• 제29권2호
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• pp.229-253
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• 2016

As a generalization of (i, j)-weakly m-continuous functions [43], we introduce the notion of weakly M(i, j)-continuous functions and obtain many characterizations and some properties of the functions. We show that the function is a unified form of some functions between m-spaces and certain kinds of weakly continuous functions in bitopological spaces.

• Korean Journal of Mathematics
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• 제4권2호
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• pp.95-100
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• 1996

In this note, the notion of fuzzy almost s-continuity is introduced and some results related to this notion are obtained.

• 한국수학교육학회지시리즈A:수학교육
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• 제22권1호
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• pp.31-33
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• 1983

이 논문에서는 Norman Levin의 논문에서 나타난 semi-open의 개념을 사용하여 정의된 semi-continuous의 여러가지 성질을 조사하였고, semi-continuity를 위상공간의 first-axiom공간 pseudo-metric공간과 n-th product공간까지 조사하였으며, semi-continuous함수의 합성과 함수열의 극한과 Proximity공간의 mapping에 대하여 조사하였다. 그리고 정리의 역이 성립하지 않는 경우 반례를 들어 보였다.

• 대한수학회논문집
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• 제30권4호
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• pp.493-504
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• 2015

The aim of this paper is to present some properties of sT-continuous functions. Moreover, we obtain a characterization and preserving theorems of semi-compact, S-closed and s-closed spaces.

• Kyungpook Mathematical Journal
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• 제32권1호
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• pp.21-30
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• 1992

• 대한수학회보
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• 제47권5호
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• pp.1025-1036
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• 2010

A new class of generalized open sets in a topological space, called e-open sets, is introduced and some properties are obtained by Ekici [6]. This class is contained in the class of $\delta$-semi-preopen (or $\delta-\beta$-open) sets and weaker than both $\delta$-semiopen sets and $\delta$-preopen sets. In order to investigate some different properties we introduce two strong form of e-open sets called e-regular sets and e-$\theta$-open sets. By means of e-$\theta$-open sets we also introduce a new class of functions called strongly $\theta$-e-continuous functions which is a generalization of $\theta$-precontinuous functions. Some characterizations concerning strongly $\theta$-e-continuous functions are obtained.