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Studies on cusp singularities by the theory of formal fans

Research Project

Project/Area Number 15K13423
Research Category

Grant-in-Aid for Challenging Exploratory Research

Allocation TypeMulti-year Fund
Research Field Algebra
Research InstitutionTohoku University

Principal Investigator

Masanori Ishida  東北大学, 理学研究科, 教授 (30124548)

Project Period (FY) 2015-04-01 – 2018-03-31
Project Status Completed (Fiscal Year 2017)
Budget Amount *help
¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2016: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2015: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Keywords代数幾何学 / 代数多様体 / トーリック多様体 / カスプ特異点 / 扇 / 形式スキーム / 無限コクセター群 / 可換環 / コクセター群 / 特異点 / 凸多面体 / 鏡映群 / スキーム理論 / 形式扇
Outline of Final Research Achievements

For the toric type cusp singularities which are described by the theory of toric varieties, we tried to establish the theory of formal fans. We defined fixed formal fans and found a sufficient condition on a support function so that such a formal fan to be a fan in a classical sense. For a 4-dimensional example of cuspsingularity obtained by Tsuchihashi, we described explicitly the intersections of the four exceptional divisors at 48 ordinary quadruple points. We described toric type cusp singularities and their resolutions, which are originally defined as complex analytic isolated singularities, over a field of any characteristic by using the theory of formal schemes. They are realized as complete local rings and projective schemes over them.

Report

(4 results)
  • 2017 Annual Research Report   Final Research Report ( PDF )
  • 2016 Research-status Report
  • 2015 Research-status Report
  • Research Products

    (4 results)

All 2017 2016 2015

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

  • [Journal Article] Cusp singularities and quasi-polyhedral sets2017

    • Author(s)
      Masanori Ishida
    • Journal Title

      Adv. Studies in Pure Math.

      Volume: 75 Pages: 163-182

    • Related Report
      2017 Annual Research Report
    • Peer Reviewed
  • [Presentation] 非有界凸多面体とトーリック型カスプ特異点2017

    • Author(s)
      石田 正典
    • Organizer
      代数学シンポジウム
    • Related Report
      2017 Annual Research Report
    • Invited
  • [Presentation] トーリック型カスプ特異点について2016

    • Author(s)
      石田 正典
    • Organizer
      代数幾何セミナー
    • Place of Presentation
      東北大学大学院理学研究科
    • Related Report
      2016 Research-status Report
  • [Presentation] 固定形式扇とトーリック型カスプ特異点2015

    • Author(s)
      石田 正典
    • Organizer
      杜の都代数幾何研究集会@福岡
    • Place of Presentation
      福岡大学セミナーハウス
    • Year and Date
      2015-11-25
    • Related Report
      2015 Research-status Report
    • Invited

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Published: 2015-04-16   Modified: 2019-03-29  

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