• Title/Summary/Keyword: differential equations of geodesics

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FINSLER SPACES WITH INFINITE SERIES (α, β)-METRIC

  • Lee, Il-Yong;Park, Hong-Suh
    • Journal of the Korean Mathematical Society
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    • v.41 no.3
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    • pp.567-589
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    • 2004
  • In the present paper, we treat an infinite series ($\alpha$, $\beta$)-metric L =$\beta$$^2$/($\beta$-$\alpha$). First, we find the conditions that a Finsler metric F$^{n}$ with the metric above be a Berwald space, a Douglas space, and a projectively flat Finsler space, respectively. Next, we investigate the condition that a two-dimensional Finsler space with the metric above be a Landsbeg space. Then the differential equations of the geodesics are also discussed.

SLANT HELICES IN THE THREE-DIMENSIONAL SPHERE

  • Lucas, Pascual;Ortega-Yagues, Jose Antonio
    • Journal of the Korean Mathematical Society
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    • v.54 no.4
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    • pp.1331-1343
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    • 2017
  • A curve ${\gamma}$ immersed in the three-dimensional sphere ${\mathbb{S}}^3$ is said to be a slant helix if there exists a Killing vector field V(s) with constant length along ${\gamma}$ and such that the angle between V and the principal normal is constant along ${\gamma}$. In this paper we characterize slant helices in ${\mathbb{S}}^3$ by means of a differential equation in the curvature ${\kappa}$ and the torsion ${\tau}$ of the curve. We define a helix surface in ${\mathbb{S}}^3$ and give a method to construct any helix surface. This method is based on the Kitagawa representation of flat surfaces in ${\mathbb{S}}^3$. Finally, we obtain a geometric approach to the problem of solving natural equations for slant helices in the three-dimensional sphere. We prove that the slant helices in ${\mathbb{S}}^3$ are exactly the geodesics of helix surfaces.