• Bulletin of the Korean Mathematical Society
• /
• v.35 no.3
• /
• pp.515-525
• /
• 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.

• Communications of the Korean Mathematical Society
• /
• v.24 no.3
• /
• pp.333-339
• /
• 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.

• Journal of the Chungcheong Mathematical Society
• /
• v.9 no.1
• /
• pp.17-25
• /
• 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.

• Communications of the Korean Mathematical Society
• /
• v.27 no.3
• /
• pp.465-475
• /
• 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
• /
• v.19 no.3
• /
• pp.321-330
• /
• 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
• /
• v.16 no.3
• /
• pp.403-412
• /
• 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.

• Bulletin of the Korean Mathematical Society
• /
• v.42 no.2
• /
• pp.307-313
• /
• 2005

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

• The Pure and Applied Mathematics
• /
• v.3 no.2
• /
• pp.117-122
• /
• 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 $J(\chi){\neq}{\phi}{\subset}M$.

• Journal of the Chungcheong Mathematical Society
• /
• v.7 no.1
• /
• pp.87-95
• /
• 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.

• The Pure and Applied Mathematics
• /
• v.16 no.4
• /
• pp.417-425
• /
• 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 $L^n$.