• Journal of the Chungcheong Mathematical Society
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• v.37 no.1
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• pp.19-26
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• 2024

In this paper, we investigate the properties related to algebraic spectral subspaces and divisible subspaces of linear operators on a Banach space. In addition, using the concept of topological divisior of zero of a Banach algebra, we prove that the only closed divisible subspace of a bounded linear operator on a Banach space is trivial. We also give an example of a bounded linear operator on a Banach space with non-trivial divisible subspaces.

• Honam Mathematical Journal
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• v.26 no.3
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• pp.341-353
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• 2004

We denote by ${{\mathcal{Q}}(A)}$ the set of all matrices with the same sign pattern as A. A matrix A has signed null-space provided there exists a set ${\mathcal{S}}$ of sign patterns such that the set of sign patterns of vectors in the null-space of ${\tilde{A}}$ is ${\mathcal{S}}$, for each ${\tilde{A}}{\in}{{\mathcal{Q}}(A)}$. Some properties of matrices with signed null-spaces are investigated.

• Communications of the Korean Mathematical Society
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• v.34 no.2
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• pp.429-437
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• 2019

Dilcher and Stolarsky [1] recently studied a sequence resembling the Chebyshev polynomials of the first kind. In this paper, we follow their some research directions to the Chebyshev polynomials of the second kind. More specifically, we consider a sequence resembling the Chebyshev polynomials of the second kind in two different ways, and investigate its properties including relations between this sequence and the sequence studied in [1], zero distribution and the irreducibility.

• Journal of applied mathematics & informatics
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• v.37 no.1_2
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• pp.37-52
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• 2019

In this paper we introduce a new concept for Riesz almost lacunary ${\chi}^3$ sequence spaces strong P - convergent to zero with respect to an Orlicz function and examine some properties of the resulting sequence spaces. We introduce and study statistical convergence of Riesz almost lacunary ${\chi}^3$ sequence spaces and some inclusion theorems are discussed.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.726-729
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• 1995

We investigated the effects of Sm on the microstructure and magnetic properties of Fe-Co Alloy films prepared by a DC triode sputtering. The magnetostriction was found to be changed with the Sm content from positive to negative values, taking a zero magnetostriction was at about 3 at% Sm. The Sm content dependence of magnetostriction was explained by the formation of Sm enriched amorphous phase surrounding the main bcc (Fe,Co) crystalline phase, which was observed by a high resolution transmission electron microscopy.

• Theoretical Mathematics and Pedagogical Mathematics
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• v.17 no.2
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• pp.131-136
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• 2010

Throught this paper, we will investigate some properties of left regular and strongly reduced near-rings. Mason introduced the notion of left regularity and he characterized left regular zero-symmetric unital near-rings. Also, this concept have been studied by several authors. The purpose of this paper is to find some characterizations of the strong reducibility in near-rings, and the strong regularity in near-rings which are closely related with strongly reduced near-rings.

• Korean Journal of Mathematics
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• v.23 no.1
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• pp.171-180
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• 2015

It is discovered in [7] that a dielectric material is coated by a plasmonic material of negative permittivity with dissipation, then cloaking by anomalous localized resonance may occur as the dissipation tends to zero. In this paper, we investigate numerically the pointwise behavior of the potential in the shell when cloaking by anomalous localized resonance (CALR) occurs. By changing locations a dipole source, we can observe some localizing properties of the potential in the shell.

• Theoretical Mathematics and Pedagogical Mathematics
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• v.18 no.4
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• pp.305-312
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• 2011

In this paper, we denote that R is a near-ring and G an R-group. We initiate the study of the substructures of R and G. Next, we investigate some properties of R-groups, d.g. near-rings and monogenic (R, S)-groups.

• Honam Mathematical Journal
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• v.26 no.1
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• pp.3-15
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• 2004

In the fuzzy theory, a matrix A is idempotent if $A^2=A$. The idempotent fuzzy matrices are important in various applications and have many interesting properties. Using the upper diagonal completion process, we have the zero patterns of idempotent fuzzy matrix, that is, the idempotent Boolean matrices. In addition, we give the construction of all idempotent fuzzy matrices for each dimension n.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.578-583
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• 1992

In this paper, we show that various navigation constant values in PNG law can result in as optimal gains when we introduce proper time-varying weighting functions into the cost function of an optimal control problem. we then apply this idea to the guidance problem where we are required to achieve a given impact angle as well as the zero miss distance. As a result, we obtain a set of optimal guidance laws each of which could be related to a navigation constant in PNG. Some basic properties of these guidance laws are also presented.