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Fundamental groups and moduli spaces of curves in positive characteristic

Research Project

Project/Area Number 20K14283
Research Category

Grant-in-Aid for Early-Career Scientists

Allocation TypeMulti-year Fund
Review Section Basic Section 11010:Algebra-related
Research InstitutionKyoto University

Principal Investigator

YANG YU  京都大学, 数理解析研究所, 特定助教 (30838131)

Project Period (FY) 2020-04-01 – 2024-03-31
Project Status Completed (Fiscal Year 2023)
Budget Amount *help
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2023: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2022: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2021: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2020: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Keywordscurve / moduli space / fundamental group / anabelian geometry / positive characteristic / pointed stable curve / 基本群 / 点付き安定曲線 / 正標数
Outline of Research at the Start

近年、申請者による、正標数代数閉体上の曲線の基本群から曲線のmoduli空間を位相空間として復元できるという新しい現象を発見した。この視点によると、申請者が基本群のmoduli空間を導入し、そして曲線のmoduli空間から基本群のmoduli空間への自然な連続写像が存在することを示した。さらに、この連続写像はhomeomorphismであることを予想し、moduli空間が一次元である場合にこの予想を示すことが成功した。この新しい現象と哲学によって、基本群のmoduli空間の位相的な性質と正標数代数閉体上の曲線のanabelian性質と一対一になっている、沢山の新しい問題が現れた。

Outline of Final Research Achievements

I introduced a new topological space called the moduli space of fundamental groups and formulated the conjecture of topological isomorphism. I also proved that this topological isomorphism conjecture holds for one-dimensional moduli spaces. By using the moduli space of fundamental groups, I posed a new anabelian philosophy for curves over algebraically closed fields of positive characteristic. Furthermore, based on this philosophy, I formulated numerous new conjectures. As an application of the philosophy, I successfully provided a new proof for the famous theorem of Mochizuki concerning the Isom version of the Grothendieck conjecture for curves over sub-p-adic fields.

Academic Significance and Societal Importance of the Research Achievements

私の研究では、基本群のモジュライ空間という新たな理論を提唱し、いくつかの基本的な予想を定式化し、その予想が成り立つ証拠も提供した。基本群のモジュライ空間理論は、正標数の代数閉体上の曲線の遠アーベル幾何学に対する一般的な哲学を提供し、特にその主予想である位相同型予想は、今後の研究の方向性を指し示している。

Report

(5 results)
  • 2023 Annual Research Report   Final Research Report ( PDF )
  • 2022 Research-status Report
  • 2021 Research-status Report
  • 2020 Research-status Report
  • Research Products

    (17 results)

All 2023 2022 2021 2020

All Journal Article (4 results) (of which Peer Reviewed: 4 results) Presentation (12 results) (of which Int'l Joint Research: 5 results,  Invited: 10 results) Funded Workshop (1 results)

  • [Journal Article] On topological and combinatorial structures of pointed stable curves over algebraically closed fields of positive characteristic2023

    • Author(s)
      Yang Yu
    • Journal Title

      Mathematische Nachrichten

      Volume: 296 Issue: 8 Pages: 3740-3781

    • DOI

      10.1002/mana.202100053

    • Related Report
      2023 Annual Research Report 2022 Research-status Report
    • Peer Reviewed
  • [Journal Article] Maximum generalized Hasse-Witt invariants and their applications to anabelian geometry2022

    • Author(s)
      Yu Yang
    • Journal Title

      Selecta Math. (N.S.)

      Volume: 28 No.5 Issue: 1 Pages: 1-98

    • DOI

      10.1007/s00029-021-00720-8

    • Related Report
      2021 Research-status Report
    • Peer Reviewed
  • [Journal Article] Raynaud-Tamagawa theta divisors and new-ordinariness of ramified coverings of curves2021

    • Author(s)
      Yu Yang
    • Journal Title

      J. Algebra

      Volume: 587 Pages: 263-294

    • DOI

      10.1016/j.jalgebra.2021.07.032

    • Related Report
      2021 Research-status Report
    • Peer Reviewed
  • [Journal Article] On the averages of generalized Hasse?Witt invariants of pointed stable curves in positive characteristic2020

    • Author(s)
      Yang Yu
    • Journal Title

      Mathematische Zeitschrift

      Volume: 295 Issue: 1-2 Pages: 1-45

    • DOI

      10.1007/s00209-019-02329-2

    • Related Report
      2020 Research-status Report
    • Peer Reviewed
  • [Presentation] Arithmetic fundamental groups of curves over local fields2023

    • Author(s)
      Yu Yang
    • Organizer
      Tokyo Institute of Technology
    • Related Report
      2023 Annual Research Report
    • Invited
  • [Presentation] Moduli spaces of fundamental groups in positive characteristic2023

    • Author(s)
      Yu Yang
    • Organizer
      The University of Arizona
    • Related Report
      2023 Annual Research Report
    • Invited
  • [Presentation] Fundamental groups of curves in positive characteristic as local moduli2023

    • Author(s)
      Yu Yang
    • Organizer
      MFO-RIMS Tandem Workshop 2023: Arithmetic Homotopy and Galois Theory
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Fundamental groups of curves in positive characteristic as local moduli2023

    • Author(s)
      Yu Yang
    • Organizer
      Algebraic Number Theory and Related Topics 2023
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Arithmetic fundamental groups of curves over local fields2023

    • Author(s)
      Yu Yang
    • Organizer
      Number theory and Geometry Seminar, Tokyo Institute of Technology, Tokyo, Japan.
    • Related Report
      2022 Research-status Report
  • [Presentation] Moduli spaces of fundamental groups in positive characteristic2023

    • Author(s)
      Yu Yang
    • Organizer
      Algebra and Number Theory Seminar, The University of Arizona, USA.
    • Related Report
      2022 Research-status Report
    • Invited
  • [Presentation] Fundamental groups of curves in positive characteristic, following Pop, Raynaud, Sa\"idi, Tamagawa, and myself2022

    • Author(s)
      Yu Yang
    • Organizer
      Colloquium, RIMS, Kyoto university, Kyoto, Japan.
    • Related Report
      2022 Research-status Report
    • Invited
  • [Presentation] Local Torelli for semi-Prym schemes2022

    • Author(s)
      Yu Yang
    • Organizer
      Sichuan University, Chengdu, China.
    • Related Report
      2022 Research-status Report
    • Invited
  • [Presentation] Moduli spaces of fundamental groups of curves in positive characteristic2021

    • Author(s)
      Yu Yang
    • Organizer
      Foundations and Perspectives of Anabelian Geometry
    • Related Report
      2021 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] Reconstructions of geometric data of pointed stable curves in positive characteristic2021

    • Author(s)
      Yu Yang
    • Organizer
      Combinatorial Anabelian Geometry and Related Topics
    • Related Report
      2021 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] Anabelian geometry of curves via moduli spaces of fundamental groups2021

    • Author(s)
      Yu Yang
    • Organizer
      Summary School on Arithemtic Geometry
    • Related Report
      2021 Research-status Report
    • Invited
  • [Presentation] Constructions of Hodge Theaters I,II2021

    • Author(s)
      Yu Yang
    • Organizer
      Invitation to inter-universal Teichmuller Theory (IUT)
    • Related Report
      2021 Research-status Report
    • Int'l Joint Research / Invited
  • [Funded Workshop] 5th Kyoto+ Workshop on Arithmetic and Geometry2023

    • Related Report
      2023 Annual Research Report

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Published: 2020-04-28   Modified: 2025-01-30  

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