• 대한수학회지
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• 제57권4호
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• pp.893-913
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• 2020

Let 𝓢 be the collection of the operator matrices $\(\array{A&C\\Z&B}\)$ where the range of C is closed. In this paper, we study the properties of operator matrices in the class 𝓢. We first explore various local spectral relations, that is, the property (β), decomposable, and the property (C) between the operator matrices in the class 𝓢 and their component operators. Moreover, we investigate Weyl and Browder type spectra of operator matrices in the class 𝓢, and as some applications, we provide the conditions for such operator matrices to satisfy a-Weyl's theorem and a-Browder's theorem, respectively.

• 한국수학사학회지
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• 제26권1호
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• pp.85-101
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• 2013

이 연구에서는 수학사에 대한 해석학적 관점에서 Barrow 정리의 특징에 대해 분석하고, 현대적인 역사발생적 원리에 기초해 수학적 재발명 활동을 이끄는 미적분학 교수-학습 계열에 대해 논의한다. Barrow 정리에 대한 수학사적 분석을 통해서는, 그 정리의 기하학적 특성을 드러내고, 그 정리를 다룬 Barrow의 의도에 대해 추측하고, Barrow가 겪은 인식론적 장애에 대해 고찰하였다. 그리고 이러한 분석을 바탕으로 하여, 학생들이 '적분'과 '미분의 역'이 같다는 것을 인식하도록 하기 위한 목적 지향적이고 의미 지향적 교수-학습을 제안하고 현재 학교수학 미적분학에서 보완해야 할 사항에 대해 지적하였다.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제17권2호
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• pp.175-183
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• 2010

Using Darbo's fixed point theorem, we establish the existence of monotone solutions for a nonlinear quadratic integral equation of Volterra type in the Banach space of real functions defined and continuous on a bounded and closed interval.

• 대한수학회보
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• 제54권6호
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• pp.2081-2089
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• 2017

In this paper we generalize 3-dimensional Bour's Theorem to the case of 4-dimension. We proved that a helicoidal surface in $\mathbb{R}^4$ is isometric to a family of surfaces of revolution in $\mathbb{R}^4$ in such a way that helices on the helicoidal surface correspond to parallel circles on the surfaces of revolution. Moreover, if the surfaces are required further to have the same Gauss map, then they are hyperplanar and minimal. Parametrizations for such minimal surfaces are given explicitly.

• 대한수학회지
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• 제39권1호
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• pp.13-30
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• 2002

A generalization of Liouville's theorem on integration in finite terms, by enlarging the class of fields to an extension called Ei-Gamma extension is established. This extension includes the $\varepsilon$L-elementary extension of Singer, Saunders and Caviness and contains the Gamma function.

• 대한수학회논문집
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• 제33권3호
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• pp.853-869
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• 2018

We give a new characterization of Browder's theorem through equality between the pseudo B-Weyl spectrum and the generalized Drazin spectrum. Also, we will give conditions under which pseudo B-Fredholm and pseudo B-Weyl spectrum introduced in [9] and [25] become stable under commuting Riesz perturbations.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제6권1호
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• pp.70-76
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• 2006

Some Stampacchia type of generalized weak vector quasivariational-like inequalities for fuzzy mappings was introduced and the existence of solutions to them under non-compact assumption was considered using the particular form of the generalized Ky Fan's section theorem due to Park [15]. As a corollary, Stampacchia type of generalized vector quasivariational-like inequalities for fuzzy mappings was studied under compact assumption using Ky Fan's section theorem [7].

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제20권4호
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• pp.587-594
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• 2006

In this paper we introduce a method of factorizing multi-variable polynomials using Viete's theorem and show some examples of factorizing multi-variable polynomials. We also discuss some aspects of this method.

• 대한수학회논문집
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• 제29권3호
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• pp.401-408
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• 2014

If A is a unital Banach algebra, then the spectrum can be viewed as a function ${\sigma}$ : 𝕬 ${\rightarrow}$ 𝕾, mapping each T ${\in}$ 𝕬 to its spectrum ${\sigma}(T)$, where 𝕾 is the set, equipped with the Hausdorff metric, of all compact subsets of $\mathbb{C}$. This paper is concerned with the continuity of the spectrum ${\sigma}$ via Browder's theorem. It is shown that ${\sigma}$ is continuous when ${\sigma}$ is restricted to the set of essentially hyponormal operators for which Browder's theorem holds, that is, the Weyl spectrum and the Browder spectrum coincide.

• 논리연구
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• 제15권3호
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• pp.307-322
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• 2012

프리드먼에 의해 제안된 "크루스칼 정리의 소형화 정리"가 2차 페아노 공리체계의 부분 시스템인 $(\prod_{2}^{1}-BI)_0$에서 증명될 수 없음을 증명한다. 또한 위 증명이 크루스칼 정리와 관련된 기존의 연구에서 알려진 중요한 정리들을 잘 조합함으로 해서 가능함을 보인다.