• 호남수학학술지
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• 제30권4호
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• pp.743-748
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• 2008

In this article, we study ruled hypersurfaces in a Lorentz-Minkowski space which has finite type immersion. As a result, we give a complete classification of ruled hypersurfaces or finite type immersion into a Lorentz-Minkowski space ${\mathbb{L}}^m$.

• Kyungpook Mathematical Journal
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• 제47권4호
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• pp.579-593
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• 2007

In this paper, we study some properties of ruled surfaces in a three-dimensional Lorentz-Minkowski space related to their Gaussian curvature, the second Gaussian curvature and the mean curvature. Furthermore, we examine the ruled surfaces in a three-dimensional Lorentz-Minkowski space satisfying the Jacobi condition formed with those curvatures, which are called the II-W and the II-G ruled surfaces and give a classification of such ruled surfaces in a three-dimensional Lorentz-Minkowski space.

• Korean Journal of Mathematics
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• 제27권4호
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• pp.1149-1157
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• 2019

We prove the Frenet type formulae for smooth one-parameter family of 2-planes or 3-planes in the Lorentz-Minkowski space 𝕃⁶. We consider two cases separately: the planes are spacelike or the planes are timelike.

• 대한수학회보
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• 제53권1호
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• pp.227-245
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• 2016

A generalized constant ratio surface (GCR surface) is defined by the property that the tangential component of the position vector is a principal direction at each point on the surface, see [8] for details. In this paper, by solving some differential equations, a complete classification of Lorentz GCR surfaces in the three-dimensional Minkowski space is presented. Moreover, it turns out that a flat Lorentz GCR surface is an open part of a cylinder, apart from a plane and a CMC Lorentz GCR surface is a surface of revolution.

• 대한수학회보
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• 제26권1호
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• pp.75-82
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• 1989

It is recently proved by Aiyama and the authors [2] that a complete space-like complex submanifold of a complex space form $M^{n+p}$$_{p}$ (c') (c'.geq.0) is to totally geodesic. This is a complex version of the Bernstein-type theorem in the Minkowski space due to Calabi [4] and Cheng and Yau [5], which is generalized by Nishikawa[7] in the Lorentz manifold satisfying the strong energy condition. The purpose of this paper is to consider his result in the complex Lorentz manifold and is to prove the following.e following.

• 대한수학회보
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• 제60권5호
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• pp.1299-1320
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• 2023

In the present paper, firstly we obtain the general expression of the canal hypersurfaces that are formed as the envelope of a family of pseudo hyperspheres, pseudo hyperbolic hyperspheres and null hyper-cones whose centers lie on a non-null curve with non-null Frenet vector fields in E⁴₁ and give their some geometric invariants such as unit normal vector fields, Gaussian curvatures, mean curvatures and principal curvatures. Also, we give some results about their flatness and minimality conditions and Weingarten canal hypersurfaces. Also, we obtain these characterizations for tubular hypersurfaces in E⁴₁ by taking constant radius function and finally, we construct some examples and visualize them with the aid of Mathematica.

• 대한수학회지
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• 제34권2호
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• pp.265-277
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• 1997

Let E be a real, non-degenerate, indefinite inner product space with dim $E \geq 3$. It is shown that any bijection of E which preserves the light cones is an affine map.

• 대한수학회지
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• 제52권3호
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• pp.523-535
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• 2015

We study surfaces in Euclidean space which are obtained as the sum of two curves or that are graphs of the product of two functions. We consider the problem of finding all these surfaces with constant Gauss curvature. We extend the results to non-degenerate surfaces in Lorentz-Minkowski space.

• 한국수학사학회지
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• 제23권4호
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• pp.31-46
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• 2010

본 논문에서는 국제 수학올림피아드(IMO)에서 최상위 그룹에 속해있는 한국, 중국, 미국의 수학 영재교육의 실태를 비교 분석하고 이들 국가에서는 수학 영재교육을 위해 어떠한 측면을 강조하고 있는지 알아본다. 또 최근의 국제 수학올림피아드(IMO)와 수학 과학 성취도 추이변화 국제비교연구(TIMSS)의 결과를 통해서 앞으로의 우리나라 수학 영재교육이 나아갈 방향을 알아본다.

• 한국수학사학회지
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• 제21권1호
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• pp.45-78
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• 2008

극소곡면은 고전미분기하학의 꽃이며 현대에 이르기까지 기하학의 중심을 이루고 있다. 이러한 극소곡면 이론에서 가장 어려운 부분이라고 할 수 있는 극소곡면의 발견 과정을 역사적으로 조명하여 보고 이를 통하여 극소곡면 이론을 소개한다. 한편 최근에 들어 연구가 시작된 로렌츠-민코프스키 공간의 극대곡면의 예를 소개하고 극소곡면 발견 과정과 비교 연구한다.