• 한국수학사학회지
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• 제28권3호
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• pp.133-149
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• 2015

Arrivals of Hilbert and Minkowski at $G\ddot{o}ttingen$ put mathematical science there in full flourish. They further extended its strong mathematical tradition of Gauss and Riemann. Though Riemann envisioned Finsler metric and gave an example of it in his inaugural lecture of 1854, Finsler geometry was officially named after Minkowski's academic grandson Finsler. His tool to generalize Riemannian geometry was the calculus of variations of which his advisor $Carath\acute{e}odory$ was a master. Another $G\ddot{o}ttingen$ graduate Busemann regraded Finsler geometry as a special case of geometry of metric spaces. He was a student of Courant who was a student of Hilbert. These figures all at $G\ddot{o}ttingen$ created and developed Finsler geometry in its early stages. In this paper, we investigate history of works on Finsler geometry contributed by these frontiers.

• 대한수학교육학회지:학교수학
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• 제9권4호
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• pp.523-533
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• 2007

이 논문에서는 피타고라스 정리에 대한 피타고라스와 유클리드의 증명의 의미를 역사적, 수학적 관점에서 고찰하였다. 피타고라스의 닮음비에 의한 증명 방법은 통약성이라는 수에 대한 가정에 근거한 것이라고 볼 수 있다. 반면 유클리드는 통약성이 필요 없는 분해 합동이라는 순수한 기하학적 방법으로 다시 증명하였다. 피타고라스 정리의 증명에서 엿볼 수 있는 피타고라스와 유클리드의 기하에 대한 다른 접근 방식을 현 학교 기하의 바탕이 되는 Birkhoff와 Hither 공리계와 연관하여 논의하였다. Birkhoff는 엄밀하게 정의된 실수 개념을 상식으로 수용하여 현대수학적인 평면 기하 공리계를 제안하였으며, Hilbert는 실수 개념에 의존하지 않는 순수한 기하학을 추구했던 유클리드적 정신을 계승하였다. 따라서 피타고라스 정리에 대한 닮음비와 분해합동을 이용한 증명, 또 넓이에 의한 증명과 넓이가 같음에 의한 증명의 차이는 전통적인 유클리드의 종합기하적 전개와 현대수학적 전개사이의 갈등이라는 기하 교육에서 아직도 완전히 해결되지 않은 논점과 관련이 있다.

• 한국수학사학회지
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• 제32권5호
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• pp.241-255
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• 2019

The proposition that the parallel axiom and the Pythagorean theorem are equivalent in the Hilbert geometry is true when the Archimedean axiom is assumed. In this article, we examine some specific plane geometries to see the existence of the non-archimidean Hilbert geometry in which the Pythagorean theorem holds but the parallel axiom does not. Furthermore we observe that the Pythagorean theorem is equivalent to the fact that the Hilbert geometry is actually a semi-Euclidean geometry.

• 한국수학사학회지
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• 제31권6호
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• pp.315-337
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• 2018

Pythagorean thoerem exists in several equivalent forms in the Euclidean plane, that is, the Hilbert plane which in addition satisfies the parallel axiom. In this article, we investigate the truthness and mutual relationships of those propositions in various non-Hilbert planes which satisfy the parallel axiom and all the Hilbert axioms except the SAS axiom.

• Korean Journal of Mathematics
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• 제17권2호
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• pp.219-231
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• 2009

We show the existence of at least four solutions for the perturbed parabolic equation with Dirichlet boundary condition and periodic condition when the nonlinear part cross two eigenvalues of the eigenvalue problem of the Laplace operator with boundary condition. We obtain this result by using the Leray-Schauder degree theory, the finite dimensional reduction method and the geometry of the mapping. The main point is that we restrict ourselves to the real Hilbert space instead of the complex space.

• 대한수학회보
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• 제55권4호
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• pp.1221-1230
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• 2018

We derive a sharp decomposition formula for the state polytope of the Hilbert point and the Hilbert-Mumford index of reducible varieties by using the decomposition of characters and basic convex geometry. This proof captures the essence of the decomposition of the state polytopes in general, and considerably simplifies an earlier proof by the authors which uses a careful analysis of initial ideals of reducible varieties.

• 충청수학회지
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• 제22권2호
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• pp.251-259
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• 2009

We investigate the multiple solutions for the nonlinear parabolic boundary value problem with jumping nonlinearity crossing two eigenvalues. We show the existence of at least four nontrivial periodic solutions for the parabolic boundary value problem. We restrict ourselves to the real Hilbert space and obtain this result by the geometry of the mapping.

• Journal of applied mathematics & informatics
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• 제29권1_2호
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• pp.443-450
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• 2011

In this paper, we construct a Gorenstein Artinian algebra R/J with non-unimodal Hilbert function h = (1, 13, 12, 13, 1) to investigate the algebraic structure of the ideal J in a polynomial ring R. For this purpose, we use a software system Macaulay 2, which is devoted to supporting research in algebraic geometry and commutative algebra.

• 한국수학사학회지
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• 제12권2호
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• pp.25-39
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• 1999

In Euclidean plane geometry, areas of polygons can be computed through a finite process of cutting and pasting. The Hilbert's third problem is that a theory of volume can not be based on the idea of cutting and pasting. This problem was solved by Dehn a few months after it was posed. The purpose of this article is not only to study Hilbert's third Problem and its proof but also to provide basis for the secondary school mathematics.

• Journal of the Korean Statistical Society
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• 제31권3호
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• pp.329-342
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• 2002

We deal with asymptotic properties of Maximum Likelihood Estimator(MLE) for the parameters appearing in a Hilbert space-valued Stochastic Differential Equation(SDE) and a Stochastic Partial Differential Equation(SPDE). In paractice, the available data are only the finite dimensional projections to the solution of the equation. Using these data we obtain MLE and consider the asymptotic properties as the dimension of projections increases. In particular we explore a relationship between the conditions for the solution and asymptotic properties of MLE.