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2005 Fiscal Year Final Research Report Summary

Integrable geodesic flows and related problems

Research Project

Project/Area Number 16540069
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Geometry
Research InstitutionOkayama University

Principal Investigator

KIYOHARA Kazuyoshi  Okayama Univ., Grad School of Natural Sci., Prof., 大学院・自然科学研究科, 教授 (80153245)

Co-Investigator(Kenkyū-buntansha) KATSUDA Atsushi  Okayama Univ., Grad School of Natural Sci., Assoc.Prof., 大学院・自然科学研究科, 助教授 (60183779)
IKEDA Akira  Okayama Univ., Fac.Edu., Prof., 教育学部, 教授 (30093363)
SAKAI Takashi  Okayama Univ.Sci., Fac.Sci., Prof., 理学部, 教授 (70005809)
ITOH Jin-ichi  Kumamoto Univ., Fac.Edu., Prof., 教育学部, 教授 (20193493)
IGARASHI Masayuki  Sci.Univ.Tokyo, Fac.Ind.Sci.of Tech., Assoc.Prof., 基礎工学部, 助教授 (60256675)
Project Period (FY) 2004 – 2005
Keywordsellipsoid / cut locus / conjugate locus / Liouville manifold / Jacobi / Integrable geodesic flow / tri-axial ellipsoid / quadratic surface
Research Abstract

We made a series of researches on "cut locus". First, we showed that the cut locus of any point on two-dimensional ellipsoids which is not an umbilic point is a segment of the curvature line passing through the antipodal point. Moreover, we proved that the conjugate locus of that point has exactly four cusps, and they appear on the two curvature lines passing through the antipodal point. The latter result was stated in Jacobi's "Lectures on dynamical systems" in the case of rotational ellipsoids, and had remained unproved.
Secondly, we showed that on certain Liouville surfaces including the ellipsoids the cut locus of a general point is "simple", i.e., a curve segment in compact case, and either empty or a curve segment or two curve segments in noncompact case. In particular, in the case of (a connected component of) two-sheeted hyperboloids, it was proved that there are two cases : In one case all of the above three types of cut loci appear ; and in the other case only connected cut loci appear. Thirdly, we proved that for a certain class of Liouville manifold diffeomorphic to the sphere, the cut locus of a general point is diffeomorphic to the closed disk of codimension one.. In particular, this class contains the ellipsoids whose principal axes have distinct length.
Also, we studied "Hermite-Liouville manifolds", which are not necessarily Kaehler-Liouville manifolds, and completely determined their local structures. Among them are involved the cases where the infintesimal automorphisms are not associated. Moreover, we constructed Hermite-Liouville manifolds over the complex projective space as a complexification of real Liouville manifolds over the real projective space. Our construction involves the parameters which almost meets the local possibility.

  • Research Products

    (10 results)

All 2005 2004

All Journal Article (10 results)

  • [Journal Article] Appendix to Some metric invariants of spheres and Alexandrov paces II2005

    • Author(s)
      K.Kiyohara
    • Journal Title

      Math. J. Okayama Univ 47

      Pages: 189-191

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] On the length of the cut locus for finitely many points2005

    • Author(s)
      J.Itoh, T.Zamfirescu
    • Journal Title

      Advanced Geometry 5

      Pages: 97-105

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Simplicies passing through a hole2005

    • Author(s)
      J.Itoh, T.Zamfirescu
    • Journal Title

      J. of Geometry 83

      Pages: 65-70

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Total curvature of noncompact piecewise Riemannian 2-polyhedra2005

    • Author(s)
      J.Itoh, F.Ohtsuka
    • Journal Title

      Tsukuba J. Math. 29

      Pages: 471-493

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Gauss-type curvatures and tubes for polyhedral surfaces2005

    • Author(s)
      J.Itoh
    • Journal Title

      Kumamoto J. Math. 18

      Pages: 51-56

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Appendix to "Some metric invariants of spheres and Alexandrov spaces II"2005

    • Author(s)
      K.Kiyohara
    • Journal Title

      Math.J.Okayama Univ. 47

      Pages: 189-191

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Simplicies passing through a hole2005

    • Author(s)
      J.Itoh, T.Zamfirescu
    • Journal Title

      J.of Geometry 83

      Pages: 65-70

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Total curvature of noncompact piecewise Riemannian 2-polyhedra2005

    • Author(s)
      J.Itoh, F.Ohtsuka
    • Journal Title

      Tsukuba J.Math. 29

      Pages: 471-493

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Gauss-type curvatures and tubes for polyhedral surfaces2005

    • Author(s)
      J.Itoh
    • Journal Title

      Kumamoto J.Math. 18

      Pages: 51-56

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] The cut loci and the conjugate loci on ellipsoids2004

    • Author(s)
      K.Kiyohara, J.Itoh
    • Journal Title

      Manuscripta Math. 114

      Pages: 247-264

    • Description
      「研究成果報告書概要(和文)」より

URL: 

Published: 2007-12-13  

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