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Surface theory and low-dimensional topology by using singularity theory

Research Project

Project/Area Number 23740045
Research Category

Grant-in-Aid for Young Scientists (B)

Allocation TypeMulti-year Fund
Research Field Geometry
Research InstitutionKobe University (2012-2013)
Gifu University (2011)

Principal Investigator

SAJI Kentaro  神戸大学, 理学(系)研究科(研究院), 准教授 (70451432)

Project Period (FY) 2011 – 2014
Project Status Completed (Fiscal Year 2014)
Budget Amount *help
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2014: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2013: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2012: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2011: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Keywords特異点 / 特異点の認識問題 / カスプ辺 / ガウス写像 / モラン写像 / 線織面 / 波面 / 単純特異点 / 認識問題 / 曲率 / 平行曲面 / ミンコフスキ空間 / ジェネリック微分幾何学 / ルジャンドル特異点論
Outline of Final Research Achievements

This research was forcused on two things.
First one is criteria for singularities. About this, we got a useful criteria for Morin singulariteis where the dimensions of source and target are different. We made a mathod to construct functions which characterize the singular set of given map, and using it, we got conditions for Morin singularities. Moreover, criteria for rhamphid cusp is obtained.
Second one is to investigate surfaces with singularity using criteria for singularities. We construct a notion ``coherent tangent bundle'', giving an intrinsic formulation for wave fronts. We show Gauss-Bonnet type theorem for it and give several other applications. Furthermore, using a duality between surfaces in 3-sphere, we study conditions for cuspidal edge and swallowtail of surface whose Gauss map is a curve. Moreover, we show duality of conditions of singularities.

Report

(4 results)
  • 2014 Final Research Report ( PDF )
  • 2013 Annual Research Report
  • 2012 Research-status Report
  • 2011 Research-status Report
  • Research Products

    (20 results)

All 2014 2013 2012 2011 Other

All Journal Article (4 results) (of which Peer Reviewed: 2 results) Presentation (13 results) (of which Invited: 1 results) Remarks (3 results)

  • [Journal Article] Coherent tangent bundles and Gauss-Bonnet formulas for wave fronts2012

    • Author(s)
      Kentaro Saji, Masaaki Umehara and Kotaro Yamada
    • Journal Title

      Journal of Geometric Analysis

      Volume: vol.22 Issue: 2 Pages: 383-409

    • DOI

      10.1007/s12220-010-9193-5

    • Related Report
      2012 Research-status Report
    • Peer Reviewed
  • [Journal Article] Criteria for D4 singularities of wave fronts2011

    • Author(s)
      Saji, Kentaro
    • Journal Title

      Tohoku Math. J.

      Volume: 63 Pages: 137-147

    • Related Report
      2011 Research-status Report
    • Peer Reviewed
  • [Journal Article] Great circular surfaces in the three-sphere2011

    • Author(s)
      Izumiya, Shyuichi; Nagai, Takayuki; Saji, Kentaro
    • Journal Title

      Differential Geom. Appl.

      Volume: 29 Pages: 409-425

    • NAID

      120006459655

    • Related Report
      2011 Research-status Report
  • [Journal Article] A2-singularities of hypersurfaces with non-negative sectional curvature in Euclidean space2011

    • Author(s)
      Saji, Kentaro; Umehara, Masaaki; Yamada, Kotaro
    • Journal Title

      Kodai Math. J.

      Volume: 34 Pages: 390-409

    • NAID

      130004687956

    • Related Report
      2011 Research-status Report
  • [Presentation] Geometric invariants of non-degenerate singular points on wave fronts2014

    • Author(s)
      Kentaro Saji
    • Organizer
      The second Japanese-Spanish workshop on Differential Geometry
    • Place of Presentation
      東京工業大学
    • Related Report
      2013 Annual Research Report
  • [Presentation] モラン特異点のイソトピー2014

    • Author(s)
      佐治健太郎
    • Organizer
      日本数学会春季年会トポロジー分科会
    • Place of Presentation
      学習院大学目白キャンパス
    • Related Report
      2013 Annual Research Report
  • [Presentation] モラン写像芽のトポロジー2013

    • Author(s)
      佐治健太郎
    • Organizer
      位相幾何・微分幾何と特異点論の関わり
    • Place of Presentation
      弘前大学
    • Related Report
      2013 Annual Research Report
  • [Presentation] Geometric invariants of cuspidal edges2013

    • Author(s)
      Kentaro Saji
    • Organizer
      「Geometric Singularity Theory Polish- Japanese Singularity Theory Working Days
    • Place of Presentation
      Warsaw Center of Mathematics and Computer Science, Warsaw, Poland
    • Related Report
      2013 Annual Research Report
  • [Presentation] Isotopy of Morin singularities2013

    • Author(s)
      Kentaro Saji
    • Organizer
      Japanese-Brazilian Singularity Days
    • Place of Presentation
      Sao Paulo 大学, Sao Carlos キャンパス
    • Related Report
      2013 Annual Research Report
  • [Presentation] Geometric invariants of cuspidal edges2013

    • Author(s)
      Kentaro Saji
    • Organizer
      Theory of singularities of smooth mappings and around it
    • Place of Presentation
      数理解析研究所
    • Related Report
      2013 Annual Research Report
  • [Presentation] 可微分写像の特異点判定法とその応用I, II2013

    • Author(s)
      佐治健太郎
    • Organizer
      第7回札幌・福岡幾何学セミナー
    • Place of Presentation
      北海道大学理学部
    • Related Report
      2012 Research-status Report
    • Invited
  • [Presentation] 双曲空間内の定曲率線織面とその特異点2012

    • Author(s)
      佐治健太郎
    • Organizer
      特異点論と幾何構造
    • Place of Presentation
      長野市生涯学習センター
    • Related Report
      2012 Research-status Report
  • [Presentation] Singularities of surfaces swept by constant curvature curves2012

    • Author(s)
      Kentaro Saji
    • Organizer
      12th International Workshop on Real and Complex singularities
    • Place of Presentation
      Sao Paulo 大学, Sao Carlos キャンパス
    • Related Report
      2012 Research-status Report
  • [Presentation] 4次元多様体間の写像の臍特異点の判定法2012

    • Author(s)
      佐治健太郎
    • Organizer
      日本数学会2012年春期年会
    • Place of Presentation
      東京理科大学神楽坂キャンパス
    • Related Report
      2011 Research-status Report
  • [Presentation] Geometry of wavefronts2011

    • Author(s)
      佐治健太郎
    • Organizer
      Singularities in geometry and applications(招待講演)
    • Place of Presentation
      ポーランド、ベンドレヴォ
    • Related Report
      2011 Research-status Report
  • [Presentation] D4特異点の判定法とその応用2011

    • Author(s)
      佐治健太郎
    • Organizer
      第58回幾何学シンポジウム
    • Place of Presentation
      山口大学吉田キャンパス
    • Related Report
      2011 Research-status Report
  • [Presentation] 3次元球面内の大円織面の特異点2011

    • Author(s)
      佐治健太郎
    • Organizer
      部分多様体幾何とリー群作用2011/9(招待講演)
    • Place of Presentation
      東京理科大学森戸記念館
    • Related Report
      2011 Research-status Report
  • [Remarks] 研究費と得られた主な成果

    • URL

      http://orange2.math.kobe-u.ac.jp/HOME/saji/math/kaken.html

    • Related Report
      2013 Annual Research Report
  • [Remarks] 研究費と得られた主な成果

    • URL

      http://www.math.kobe-u.ac.jp/HOME/saji/math/kaken.html

    • Related Report
      2012 Research-status Report
  • [Remarks]

    • URL

      http://www.math.kobe-u.ac.jp/HOME/saji/math/kaken.html

    • Related Report
      2011 Research-status Report

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Published: 2011-08-05   Modified: 2019-07-29  

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