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Local-global conjecture on representation theory of finite groups

Research Project

Project/Area Number 19K03416
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 11010:Algebra-related
Research InstitutionChiba University

Principal Investigator

Koshitani Shigeo  千葉大学, 大学院理学研究院, 名誉教授 (30125926)

Project Period (FY) 2019-04-01 – 2024-03-31
Project Status Completed (Fiscal Year 2023)
Budget Amount *help
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2021: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Keywords表現論 / 有限群 / 森田同値 / pブロック / 不足群 / ブラウアー予想 / ブラウアー直既約性 / 自己準同型自明加群 / endo-trivial module / Scott module / wreath product group / Puig's conjecture / Brauer indecomposability / semi-dihedral 2-group / Schur multiplier / trivial source module / p-permutation module / special linear group / special unitary group / モジュラー表現論 / ブロック / 二面体群 / 準二面体群 / 一般四元数群 / 有限次元代数 / 既約加群 / アウスランダー・ライテン箙 / 可換不足群 / スコット加群 / 局所大域予想
Outline of Research at the Start

「群」とは、例えば、正三角形、正方形、そして壁紙、建物の床、紋章などに見られる対称性を抽象化させたものである。この対称性を維持した操作が有限の種類しか現われないときに、有限群と呼ぶ。そして線形代数に出て来る正方行列(数を縦横同じ個数だけに並べたもの)を考える。例えば2次正方行列とは、縦横合わせて4つの箱に数を入れたものになる。そして有限群を、正方行列の中でも逆行列を持つ行列たちの中で表そうとするのが、有限群の表現論である。今回の研究では、「大きい有限群の表現論」は「元の群よりずっと小さい局所群の表現論」で本質的には近似できるのではないか、という予想の解決に取り組む。

Outline of Final Research Achievements

The aim of this project is that modular representation theory with respect to a prime p of a finite G should/would be controlled by that of its normalizer of a Sylow p-subgroup P in G. More concretely speaking, Alperin-McKay conjecture, Brauer's conjectures, Dade conjecture, Broue conjecture and Donovan conjecture (Puig's finiteness conjecture), and so on. We have been able to get several new results on, first of all, Brauer's indecomposability for important three cases that should be quite useful for Broue's conjecture, and also Puig's finiteness conjecture for some cases.

Academic Significance and Societal Importance of the Research Achievements

課題は代数学での有限群の表現論(基礎体の標数は素数 )であった。有限群の表現論(大域)と、より小さい群の表現論(局所)との関係を調べ、より簡単な局所での表現論を大域へ繋げることを試みた。これに関する重要な予想(ブラウアーの通常既約指標予想、プーチの有限性予想、ブラウアー直既約性予想)に関して、幾つかの重要な場合に結果を得た。表現論における重要な寄与である。
現代社会でのセキュリティー(暗証番号等)に素数が大いに役立っているように、純粋数学内の研究であっても、実は一般社会に大いに貢献している。特に近年、AI は、純粋数学の研究を必要としている。その意味で、十分社会意義がある。

Report

(6 results)
  • 2023 Annual Research Report   Final Research Report ( PDF )
  • 2022 Research-status Report
  • 2021 Research-status Report
  • 2020 Research-status Report
  • 2019 Research-status Report
  • Research Products

    (40 results)

All 2024 2023 2022 2021 2020 2019 2018 Other

All Int'l Joint Research (15 results) Journal Article (13 results) (of which Int'l Joint Research: 10 results,  Peer Reviewed: 12 results,  Open Access: 1 results) Presentation (8 results) (of which Int'l Joint Research: 6 results,  Invited: 8 results) Remarks (4 results)

  • [Int'l Joint Research] Lindau-Kaiserslautern University(ドイツ)

    • Related Report
      2023 Annual Research Report
  • [Int'l Joint Research] Mimar Sinan Finte Arts University(トルコ)

    • Related Report
      2023 Annual Research Report
  • [Int'l Joint Research] Mlano-Bicocca University(イタリア)

    • Related Report
      2023 Annual Research Report
  • [Int'l Joint Research] Lindau-Kaiserslautern University(ドイツ)

    • Related Report
      2022 Research-status Report
  • [Int'l Joint Research] Mimar Sinan Fine Arts University(トルコ)

    • Related Report
      2022 Research-status Report
  • [Int'l Joint Research] Milano-Bicocca University(イタリア)

    • Related Report
      2022 Research-status Report
  • [Int'l Joint Research] Kaiserslautern Technical University(ドイツ)

    • Related Report
      2021 Research-status Report
  • [Int'l Joint Research] Mimar Sinan Fine Arts University(トルコ)

    • Related Report
      2021 Research-status Report
  • [Int'l Joint Research] University of Milano-Bicocca(イタリア)

    • Related Report
      2021 Research-status Report
  • [Int'l Joint Research] Kaiserslautern Technical University(ドイツ)

    • Related Report
      2020 Research-status Report
  • [Int'l Joint Research] Mimar Sinan Fine Arts University(トルコ)

    • Related Report
      2020 Research-status Report
  • [Int'l Joint Research] Universit;y of Milano-Bicocca(イタリア)

    • Related Report
      2020 Research-status Report
  • [Int'l Joint Research] Kaiserslautern Technical University(ドイツ)

    • Related Report
      2019 Research-status Report
  • [Int'l Joint Research] Mimar Sinan Fine Arts University(トルコ)

    • Related Report
      2019 Research-status Report
  • [Int'l Joint Research] University of Milano-Bicocca(イタリア)

    • Related Report
      2019 Research-status Report
  • [Journal Article] Recognition of Brauer indecomposability for a Scott module2024

    • Author(s)
      Shigeo Koshitani, Ipek Tuvay
    • Journal Title

      Journal of Algebra and Its Application

      Volume: 24 Issue: 01 Pages: 2550015-2550015

    • DOI

      10.1142/s021949882550015x

    • Related Report
      2023 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Trivial source endo-trivial modules for finite groups with semi-dihedral Sylow 2-subgroups2022

    • Author(s)
      Shigeo Koshitani and Caroline Lassueur
    • Journal Title

      Beitraege Algebra und Geometrie

      Volume: 63 Issue: 2 Pages: 233-246

    • DOI

      10.1007/s13366-021-00581-4

    • Related Report
      2022 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Splendid Morita equivalences for principal blocks with semidihedral defect groups2022

    • Author(s)
      Shigeo Koshitani, Caroline Lasueur and Benjamin Sambale
    • Journal Title

      Proceedings of the American Mathematicsl Society

      Volume: 150 Issue: 01 Pages: 41-53

    • DOI

      10.1090/proc/15631

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Brauer indecomposability of Scott modules with semidihedral vertex2021

    • Author(s)
      Shigeo Koshitani and Ipek Tuvay
    • Journal Title

      Proceedings of the Edinburgh Mathematical Society

      Volume: 64 Issue: 2 Pages: 174-182

    • DOI

      10.1017/s0013091521000067

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] The principal p-blocks with four irreducible characters2021

    • Author(s)
      Shigeo Koshitani and Taro Sakurai
    • Journal Title

      Bulletin of the London Mathematical Society

      Volume: 53 Issue: 4 Pages: 1124-1138

    • DOI

      10.1112/blms.12488

    • Related Report
      2021 Research-status Report
    • Peer Reviewed
  • [Journal Article] Trivial source characters in blocks with cyclic defect groups2021

    • Author(s)
      Shigeo Koshitani and Caroline Lassueur
    • Journal Title

      Journal of Algebra

      Volume: 574 Pages: 375-408

    • DOI

      10.1016/j.jalgebra.2021.01.020

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] The Brauer indecomposability of Scott modules with wreathed 2-group vertices2021

    • Author(s)
      Shigeo Koshitani and
    • Journal Title

      Rocky Mountain Journal of Mathematics

      Volume: 51 Issue: 4

    • DOI

      10.1216/rmj.2021.51.1259

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Splendid Morita equivalences for principal 2-blocks with dihedral defect groups2020

    • Author(s)
      Shigeo Koshitani and Caroline Lassueur
    • Journal Title

      Mathematische Zeitschrift

      Volume: 294 Issue: 1-2 Pages: 639-666

    • DOI

      10.1007/s00209-019-02301-0

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Splendid Morita equivalences for principal blocks with generalised quaternion defect groups2020

    • Author(s)
      Shigeo Koshitani and Caroline Lassueur
    • Journal Title

      Journal of Algebra

      Volume: 558 Pages: 523-533

    • DOI

      10.1016/j.jalgebra.2019.03.038

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] On theorems of Brauer-Nesbitt and Brandt for characterizations of small block algebras2019

    • Author(s)
      Shigeo Koshitani and Taro Sakurai.
    • Journal Title

      Archiv der Mathematik

      Volume: 113 Issue: 1 Pages: 1-10

    • DOI

      10.1007/s00013-019-01311-y

    • Related Report
      2019 Research-status Report
    • Peer Reviewed
  • [Journal Article] The Brauer indecomposability of Scott Modules for the Quadratic Group Qd(p)2019

    • Author(s)
      Shigeo Koshitani and Ipek Tuvay
    • Journal Title

      Algebras and Representation Theory

      Volume: 22 Issue: 6 Pages: 1387-1397

    • DOI

      10.1007/s10468-018-9825-1

    • Related Report
      2019 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] On certain Morita invariants involving commutator subspace and radical powers2019

    • Author(s)
      Shigeo Koshitani and Taro Sakurai
    • Journal Title

      Proceedings of the 51st Symposium on Ring Theory and Representation Theory

      Volume: 51

    • Related Report
      2019 Research-status Report
    • Open Access
  • [Journal Article] Simple modules in the Auslander-Reiten quiver of principal blocks with abelian defect groups2018

    • Author(s)
      S. Koshitani, C. Lassueur
    • Journal Title

      Nagoya Mathematical Journal

      Volume: 印刷中 Pages: 1-28

    • DOI

      10.1017/nmj.2017.45

    • Related Report
      2019 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Presentation] リース積シロー2-部分群を持つ有限群の主ブロック2024

    • Author(s)
      Shigeo Koshitani
    • Organizer
      有限群のコホモロジー論とその周辺 京都大学数理解析研究所
    • Related Report
      2023 Annual Research Report
    • Invited
  • [Presentation] Splendid Morita equivalences for principal 2-blocks with wreath defect groups2023

    • Author(s)
      Shigeo Koshitani
    • Organizer
      Representations of Finite Groups, Overwolfach Math. Institute, Germany
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Block algebras of finite groups and finite-dimensional symmetric algebras that have two simples2022

    • Author(s)
      Shigeo Koshitani
    • Organizer
      Bilkent Algebra Seminar, トルコ (web講演)
    • Related Report
      2022 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] What has happened, is happening and is going to happen in representation theory of finite groups?2022

    • Author(s)
      Shigeo Koshitani
    • Organizer
      Mimar Sinan University Mathematics Seminar(トルコ・イスタンブール)
    • Related Report
      2021 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] 準 2 面体群をシロー群に持つ有限群の主ブロックの splendid 森田同値2022

    • Author(s)
      Shigeo Koshitani
    • Organizer
      有限群のコホモロジー論とその周辺(京都大学数理解析研究所共同研究)
    • Related Report
      2021 Research-status Report
    • Invited
  • [Presentation] Modular representation theory of finite groups -- local versus global, I and II2022

    • Author(s)
      Shigeo Koshitani
    • Organizer
      Tokyo-Nagoya Algebra Seminar
    • Related Report
      2021 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] Block equivalences and block invariants2019

    • Author(s)
      Shigeo Koshitani
    • Organizer
      Oberseminar on Block Theory (ドイツ・Kaiserslautern Technical University)
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] A principal block with a few characters2019

    • Author(s)
      Shigeo Koshitani
    • Organizer
      Darstellungstheorietage (Representation Theory Days) 2019
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research / Invited
  • [Remarks]

    • URL

      https://www.math.s.chiba-u.ac.jp/~koshitan/index-e.html

    • Related Report
      2022 Research-status Report
  • [Remarks]

    • URL

      https://www.math.s.chiba-u.ac.jp/~koshitan/

    • Related Report
      2022 Research-status Report
  • [Remarks]

    • URL

      http://www.math.s.chiba-u.ac.jp/~koshitan/

    • Related Report
      2020 Research-status Report
  • [Remarks]

    • URL

      http://www.math.s.chiba-u.ac.jp/~koshitan/

    • Related Report
      2019 Research-status Report

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Published: 2019-04-18   Modified: 2025-01-30  

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