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1998 Fiscal Year Final Research Report Summary

Surfaces with parallel mean curvature vector in Complex projective spaces

Research Project

Project/Area Number 09640085
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Geometry
Research InstitutionYamagata U.

Principal Investigator

OGATA Takashi  Faculty of Science, Prof., 理学部, 教授 (10042425)

Co-Investigator(Kenkyū-buntansha) UCHIDA Yoshiaki  Faculty of Science, Aso.Prof., 理学部, 助教授 (80280890)
SAWADA Hideki  Faculty of Science, Aso.Prof., 理学部, 助教授 (30095856)
II Kiyotaka  Faculty of Science, Aso.Prof., 理学部, 助教授 (10007180)
HIRABUKI Shinkichi  Faculty of Science, Aso.Prof., 理学部, 助教授 (70007136)
OHIKE Hiroshi  Faculty of Science, Prof., 理学部, 教授 (20007165)
Project Period (FY) 1997 – 1998
KeywordsKaehler angle / minimal surface / complex projective space / cryptology / knot theory / Carnot space / tangent bundle / quaternion projective space
Research Abstract

The purpose of our research is to investigate properties of the complex projective space from several points of view using various kinds of method. Each investigator has aimed to develop the research using his own special knowledge and have the following research results.
Ogata, the head of this investigating team, has studied characterization and classification of surfaces with parallel mean curvature vector field in the complex projective space and proved that there exist minimal surfaces with constant Kaehler angle and non-constant Gaussian curvature in the 2-dimensional complex projective space.
Hirabuki has proved Krull-Akizuki theorem for semigroups by using the method of proving theorem for rings arising from semigroup rings.
It has constructed complex structures on the tangent bundle of the quaternion projective space by using the geometrical technique and proved that these complex structures correspond with the ones which were given by Furuya-Tanaka-Yoshizawa.
Sawada has algebrically described cryptology and considered it as a group action. Specially he has examined the structure of groups related to RSA cryptosystems and showed the existence of a pair of different keys which encrypt messages equally. These results are read at the 20-th civil lecture promoted by Japan Mathematical Society,
Uchida has proved that many periodical knots have not the DELTA-unknotting number 1. Moreover, he conjecture that the periodical unknotting number is not 1 for the usual unknotting operation.
Ueno has studied the Dirichlet problems at infinity for harmonic maps between the Carnot spaces. The obtained results are read at the research meetings held at Tokyo Metropolitan Univ. and Yamaguchi Univ..

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] 尾形隆司: "P^2(C)内のケーラー角度一定な極小曲面" 京都大学数理解析研究所講究録. 1069. 83-91 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] S.Hirabuki, R.Matsuda: "Note on the Kuull-Akizuki Theorem for Semi-groups." Bull.of Yamagata Univ. (Nat.Sci.). 14(3). 155-159 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Ii, T.Morikawa: "Kaehler structures on the tangent bundle of Riemanniau manifolds of constant positive curvature." Bull.of Yamagata Univ. (Nat.Sci.). 14(3). 141-154 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H.Sawada: "GAP in algebra class." Proceed. of the 3-rd Asiantech.conf.in Math. (spring). ATCM '98. 233-245 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Nakamura, Y.Uchida: "Delta-unknotting number for knots." J.of knot Theory and its Ravifications.7(5). 639-650 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Nagasawa, K.Ueno: "Initial-final value problems for ordinary diff.equations and App.to equivaviant harmonic maps." J.Math.Soc.Japan. 50(3). 545-555 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.OGATA: "Minimal Surfaces with constant Kaehler angle in 2-dim.complex projective spaces." RIMS Kokyuroku. 1069. 83-91 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S.Hirabuki and R.Matsuda: "Note on the Krull-Akizuki Theorem for semi-group." Bull.of Yamagata U.(Nat.Sci.). Vol.14(3). 155-159 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.II and T.Morikawa: "Kaehler structures on the tangent bundle of Riemannian manifolds of constant positive curva-ture." Bull.of Yamagata U.(Nat.Sci.). Vol.14(3). 141-154 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Sawada: "GPA in algebra class." Proceed.of the 3-rd Asian tech.conf.in Math.(Springer), ATCM'98. 233-245 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Nakamura and Y.Uchida: "Delta-unknotting number for knots." J.of Knot Theory and its Ramifications. Vol.7(5). 639-650 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Nagasawa and K.Ueno: "Initial-final value problems for ordinary diff.equations and app.to equivariant harmonic maps." J.Math.Soc.Japan. Vol.50(3). 545-555 (1998)

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

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Published: 1999-12-08  

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