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2010 Fiscal Year Final Research Report

Geometry of curves and surfaces with singularities

Research Project

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Project/Area Number 19204005
Research Category

Grant-in-Aid for Scientific Research (A)

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

Principal Investigator

UMEHARA Masaaki  Osaka University, 大学院・理学研究科, 教授 (90193945)

Co-Investigator(Kenkyū-buntansha) YAMADA Kotaro  東京工業大学, 大学院・理工学研究科, 教授 (10221657)
HASHIMOTO Hideya  名城大学, 理工学部, 教授 (60218419)
MASHIMO Katsuya  法政大学, 理工学部, 教授 (50157187)
MABUCHI Toshiki  大阪大学, 大学院・理学研究科, 教授 (80116102)
KOISO Norihito  大阪大学, 大学院・理学研究科, 教授 (70116028)
GOTO Ryushi  大阪大学, 大学院・理学研究科, 准教授 (30252571)
ENOKI Ichiro  大阪大学, 大学院・理学研究科, 准教授 (20146806)
W.F. Rossman  神戸大学, 理学部, 教授 (50284485)
MIYAOKA Reiko  東北大学, 大学院・理学研究科, 教授 (70108182)
KOKUBU Masatoshi  東京電機大学, 工学部, 教授 (50287439)
FUJIMORI Shoichi  福岡教育大学, 教育学部, 准教授 (00452706)
AGAOKA Yoshio  広島大学, 大学院・理学研究科, 教授 (50192894)
Project Period (FY) 2007 – 2010
Keywords微分幾何 / ガウス曲率 / 平均曲率 / 波面 / 特異点
Research Abstract

This research was focused on the geometry of curves and surfaces with singularities. We gave a useful criterion for A_k singular points on hypersurfaces, and applied it to the study of inflection points on hypersurfaces. This riterion enabled us to define A_k singularities of wave front without assuming the existence of an ambient space. In fact, we defined the notion "coherent tangent bundle", giving an intrinsic formulation for wave fronts and several other applications. Moreover, we investigated maximal surfaces in Lorentz-Minkowski space and constant mean curvature surfaces in de Sitter space, and constructed several interesting new examples with singularities but still having certain kind of completeness.
Additionally, the head investigator and coinvestigators held several workshops (both domestic and international), which related in many fruitful discussions with geometers studying relating fields.

  • Research Products

    (7 results)

All 2010 2009 2008

All Journal Article (6 results) (of which Peer Reviewed: 6 results) Presentation (1 results)

  • [Journal Article] Flat surfaces with singularities in Euclidean 3-space2009

    • Author(s)
      S.Murata, M.Umehara
    • Journal Title

      Journal of Differential Geometry 82

      Pages: 279-316

    • Peer Reviewed
  • [Journal Article] Complete bounded null curves immersed in C3 and PSL(2, C)2009

    • Author(s)
      F.Martin, M.Umehara, K.Yamada
    • Journal Title

      Calculus of Variations and Partial Differential Equations 36

      Pages: 119-139

    • Peer Reviewed
  • [Journal Article] Ak singularities of wave fronts2009

    • Author(s)
      K.Saji, M.Umehara, K.Yamada
    • Journal Title

      Mathematical Proceedings of the Cambridge Philosophical Society 146

      Pages: 731-746

    • Peer Reviewed
  • [Journal Article] The geometry of fronts2009

    • Author(s)
      K.Saji, M.Umehara, K.Yamada
    • Journal Title

      Ann.of Math. 169

      Pages: 491-529

    • Peer Reviewed
  • [Journal Article] Singularities of maximal surfaces2008

    • Author(s)
      S.Fujimori, K.Saji, M.Umehara, K.Yamada
    • Journal Title

      Math.Z. 259

      Pages: 827-848

    • Peer Reviewed
  • [Journal Article] Inflection points and double tangents on anti-convex curves in the real projective plane2008

    • Author(s)
      G.Thorbergsson, M.Umehara
    • Journal Title

      Tohoku Mathematical Journal 60

      Pages: 149-181

    • Peer Reviewed
  • [Presentation] 波面の幾何学-その内的双対性とGauss-Bonnetの定理への応用-2010

    • Author(s)
      梅原雅顕
    • Organizer
      日本数学会2010年度年会・企画特別講演
    • Place of Presentation
      慶應義塾大学・理工学部
    • Year and Date
      2010-03-26

URL: 

Published: 2012-01-26   Modified: 2014-06-02  

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