• Title/Summary/Keyword: Bertrand

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ON TIMELIKE BERTRAND CURVES IN MINKOWSKI 3-SPACE

  • Ucum, Ali;Ilarslan, Kazim
    • Honam Mathematical Journal
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    • v.38 no.3
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    • pp.467-477
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    • 2016
  • In this paper, we study the timelike Bertrand curves in Minkowski 3-space. Since the principal normal vector of a timelike curve is spacelike, the Bertrand mate curve of this curve can be a timelike curve, a spacelike curve with spacelike principal normal or a Cartan null curve, respectively. Thus, by considering these three cases, we get the necessary and sufficient conditions for a timelike curve to be a Bertrand curve. Also we give the related examples.

On Pseudo Null Bertrand Curves in Minkowski Space-time

  • Gok, Ismail;Nurkan, Semra Kaya;Ilarslan, Kazim
    • Kyungpook Mathematical Journal
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    • v.54 no.4
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    • pp.685-697
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    • 2014
  • In this paper, we prove that there are no pseudo null Bertrand curve with curvature functions $k_1(s)=1$, $k_2(s){\neq}0$ and $k_3(s)$ other than itself in Minkowski spacetime ${\mathbb{E}}_1^4$ and by using the similar idea of Matsuda and Yorozu [13], we define a new kind of Bertrand curve and called it pseudo null (1,3)-Bertrand curve. Also we give some characterizations and an example of pseudo null (1,3)-Bertrand curves in Minkowski spacetime.

NOTE ON BERTRAND B-PAIRS OF CURVES IN MINKOWSKI 3-SPACE

  • Ilarslan, Kazim;Ucum, Ali;Aslan, Nihal Kilic;Nesovic, Emilija
    • Honam Mathematical Journal
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    • v.40 no.3
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    • pp.561-576
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    • 2018
  • In this paper, we define null Cartan and pseudo null Bertrand curves in Minkowski space ${\mathbb{E}}^3_1$ according to their Bishop frames. We obtain the necessary and sufficient conditions for pseudo null curves to be Bertand B-curves in terms of their Bishop curvatures. We prove that there are no null Cartan curves in Minkowski 3-space which are Bertrand B-curves, by considering the cases when their Bertrand B-mate curves are spacelike, timelike, null Cartan and pseudo null curves. Finally, we give some examples of pseudo null Bertrand B-curve pairs.

CURVES ON THE UNIT 3-SPHERE S3(1) IN EUCLIDEAN 4-SPACE ℝ4

  • Kim, Chan Yong;Park, Jeonghyeong;Yorozu, Sinsuke
    • Bulletin of the Korean Mathematical Society
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    • v.50 no.5
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    • pp.1599-1622
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    • 2013
  • We show many examples of curves on the unit 2-sphere $S^2(1)$ in $\mathbb{R}^3$ and the unit 3-sphere $S^3(1)$ in $\mathbb{R}^4$. We study whether its curves are Bertrand curves or spherical Bertrand curves and provide some examples illustrating the resultant curves.

RANDOM CHORD IN A CIRCLE AND BERTRAND'S PARADOX: NEW GENERATION METHOD, EXTREME BEHAVIOUR AND LENGTH MOMENTS

  • Vidovic, Zoran
    • Bulletin of the Korean Mathematical Society
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    • v.58 no.2
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    • pp.433-444
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    • 2021
  • In this paper a new generating procedure of a random chord is presented. This problem has its roots in the Bertrand's paradox. A study of the limit behaviour of its maximum length and the rate of convergence is conducted. In addition, moments of record values of random chord length are obtained for this case, as well as other cases of solutions of Bertrand's paradox.

BERTRAND CURVES AND RAZZABONI SURFACES IN MINKOWSKI 3-SPACE

  • Xu, Chuanyou;Cao, Xifang;Zhu, Peng
    • Bulletin of the Korean Mathematical Society
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    • v.52 no.2
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    • pp.377-394
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    • 2015
  • In this paper, we generalize some results about Bertrand curves and Razzaboni surfaces in Euclidean 3-space to the case that the ambient space is Minkowski 3-space. Our discussion is divided into three different cases, i.e., the parent Bertrand curve being timelike, spacelike with timelike principal normal, and spacelike with spacelike principal normal. For each case, first we show that Razzaboni surfaces and their mates are related by a reciprocal transformation; then we give B$\ddot{a}$cklund transformations for Bertrand curves and for Razzaboni surfaces; finally we prove that the reciprocal and B$\ddot{a}$cklund transformations on Razzaboni surfaces commute.

A Study on Geometrical Probability Instruction through Analysis of Bertrand's Paradox (Bertrand's Paradox 의 분석을 통한 기하학적 확률에 관한 연구)

  • Cho, Cha-Mi;Park, Jong-Youll;Kang, Soon-Ja
    • School Mathematics
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    • v.10 no.2
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    • pp.181-197
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    • 2008
  • Bertrand's Paradox is known as a paradox because it produces different solutions when we apply different method. This essay analyzed diverse problem solving methods which result from no clear presenting of 'random chord'. The essay also tried to discover the difference between the mathematical calculation of three problem solvings and physical experiment in the real world. In the process for this, whether geometric statistic teaching related to measurement and integral calculus which is the basic concept of integral geometry is appropriate factor in current education curriculum based on Laplace's classical perspective was prudently discussed with its status.

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BERTRAND CURVES IN NON-FLAT 3-DIMENSIONAL (RIEMANNIAN OR LORENTZIAN) SPACE FORMS

  • Lucas, Pascual;Ortega-Yagues, Jose Antonio
    • Bulletin of the Korean Mathematical Society
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    • v.50 no.4
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    • pp.1109-1126
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    • 2013
  • Let $\mathbb{M}^3_q(c)$ denote the 3-dimensional space form of index $q=0,1$, and constant curvature $c{\neq}0$. A curve ${\alpha}$ immersed in $\mathbb{M}^3_q(c)$ is said to be a Bertrand curve if there exists another curve ${\beta}$ and a one-to-one correspondence between ${\alpha}$ and ${\beta}$ such that both curves have common principal normal geodesics at corresponding points. We obtain characterizations for both the cases of non-null curves and null curves. For non-null curves our theorem formally agrees with the classical one: non-null Bertrand curves in $\mathbb{M}^3_q(c)$ correspond with curves for which there exist two constants ${\lambda}{\neq}0$ and ${\mu}$ such that ${\lambda}{\kappa}+{\mu}{\tau}=1$, where ${\kappa}$ and ${\tau}$ stand for the curvature and torsion of the curve. As a consequence, non-null helices in $\mathbb{M}^3_q(c)$ are the only twisted curves in $\mathbb{M}^3_q(c)$ having infinite non-null Bertrand conjugate curves. In the case of null curves in the 3-dimensional Lorentzian space forms, we show that a null curve is a Bertrand curve if and only if it has non-zero constant second Frenet curvature. In the particular case where null curves are parametrized by the pseudo-arc length parameter, null helices are the only null Bertrand curves.