• 대한수학회보
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• 제35권3호
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• pp.515-525
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• 1998

In this paper we obtain a "compactness" result that asserts the existence, in certain sets of sequences, of a sequence which has a maximal reciprocal sum. We derive this result from a much more general theorem which will be proved by introducing a metric into the set of sequences and using a topological argument.

• 대한수학회논문집
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• 제24권3호
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• pp.333-339
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• 2009

In this manuscript, we introduce the concept of an atomic subset of the hyper BCK-algebra and study its properties. Also, we give a characterization of the atomic hyper BCK-algebra and show that there are exactly (up to isomorphism) n atomic hyper BCK-algebras H with |H| = n for any natural number n.

• 충청수학회지
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• 제9권1호
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• pp.17-25
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• 1996

We study the relationship between a property of a triangular subset and coassociated prime ideals of the module of generalized fractions induced by the triangular subset, and investigate coassociated prime ideals of modules of generalized fractions defined by some special triangular subsets.

• 대한수학회논문집
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• 제27권3호
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• pp.465-475
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• 2012

We characterize the fuzzy ideal generated by a fuzzy subset in a semigroup and the fuzzy interior ideal generated by a fuzzy subset in a semigroup. Our work generalizes the characterizations ([8]) of those fuzzy ideals generated by fuzzy subsets in semigroups with an identity element.

• Korean Journal of Mathematics
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• 제19권3호
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• pp.321-330
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• 2011

We characterize the fuzzy bi-ideal generated by a fuzzy subset in a semigroup and the fuzzy bi-ideal generated by a fuzzy subset A such that $A{\subseteq}A^2$ in a semigroup with an identity element. Our work generalizes the characterization of fuzzy bi-ideals by Mo and Wang ([8]).

• Korean Journal of Mathematics
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• 제16권3호
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• pp.403-412
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• 2008

We define the operations ${\vee}$ and ${\wedge}$ for fuzzy sets in a lattice, characterize fuzzy sublattices in terms of ${\vee}$ and ${\wedge}$, develop some properties of the distributive fuzzy sublattices, and find the fuzzy ideal generated by a fuzzy subset in a lattice and the fuzzy dual ideal generated by a fuzzy subset in a lattice.

• 대한수학회보
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• 제42권2호
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• pp.307-313
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• 2005

The Lefschetz fixed point theorem is extended to compact continuous maps defined on an admissible subset of a Hausdorff topological space.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제3권2호
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• pp.117-122
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• 1996

We investigate that if M is a compact subset of c-first countable space X, then ${\chi}{\in} A_u(M)$ if and only if $J(\chi){\neq}{\phi}{\subset}M$.

• 충청수학회지
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• 제7권1호
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• pp.87-95
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• 1994

Relationships between the prime ideals of a ring R and of a normalizing extension S have been studied by several authors. Relationships between the prime ideals of a ring R and of an intermediate normalizing extension T also have studied by several authors where $R{\subset}T{\subset}S$. In this note, some relationships between prime ideals of T and S are studied.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제16권4호
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• pp.417-425
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• 2009

In this paper we show that spheres in $E^3{\subset}L^n$ and pseudohyperbolic spaces in $L^3{\subset}L^n$ are the only totally umbilic spacelike surfaces of type (I) in $L^n$.