• 대한수학회논문집
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• 제11권3호
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• pp.557-562
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• 1996

We find an equivalent condition of $M_n(R)[x, \delta]$ to be primitive and characterize a special subring P of $M_n(R)$. Also, we find an equivalent condition of $P[x, \delta]$ to be primitive.

• 대한수학회보
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• 제57권2호
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• pp.443-447
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• 2020

For n ≥ 2, we characterize the smooth points of the unit ball of 𝓛_s(ⁿ𝑙²_∞).

• 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.

• Kyungpook Mathematical Journal
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• 제50권1호
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• pp.109-116
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• 2010

In this paper, we study the signless Laplacian spectral radius of bicyclic graphs with given number of pendant vertices and characterize the extremal graphs.

• Kyungpook Mathematical Journal
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• 제49권1호
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• pp.123-131
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• 2009

In this paper, we study the signless Laplacian spectral radius of unicyclic graphs with prescribed number of pendant vertices or independence number. We also characterize the extremal graphs completely.

• 호남수학학술지
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• 제29권4호
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• pp.589-595
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• 2007

In this paper, we introduce the concepts of the convexity hull and co-convex sets on preconvexity spaces. We study some properties for the co-convexity hull and characterize c-convex functions and c-concave functions by using the co-convexity hull and the convexity hull.

• 호남수학학술지
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• 제39권2호
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• pp.175-185
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• 2017

In this paper we consider Toeplitz operators on the pluriharmonic Dirichlet space of the unit ball in the n-dimensional complex space. We then characterize Fredholm Toeplitz operators and describe the essential spectrum of a Toeplitz operator as a consequence.

• East Asian mathematical journal
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• 제21권1호
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• pp.113-122
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• 2005

Let $\mathbb{H}^3$ be the 3-dimensional Heisenberg group equipped with a left-invariant metric. In this paper, We characterize the Gaussian curvatures of the geodesic spheres on $\mathbb{H}^3$.

• East Asian mathematical journal
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• 제24권2호
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• pp.201-212
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• 2008

We characterize operators between Banach spaces sending unconditionally weakly p-summable sequences into sequences that lie in the range of a vector measure of bounded variation. Further, we describe operators between Banach spaces taking unconditionally weakly p-summable sequences into sequences that lie in the range of a vector measure.

• 충청수학회지
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• 제20권3호
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• pp.191-201
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• 2007

In this paper we introduce the notion of congruence on a ternary semigroup and study some interesting properties. We also introduce the notions of cancellative congruence, group congruence and Rees congruence and characterize these congruences in ternary semigroups.