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Dynkin indices and totally geodesic submanifolds in Riemannian symmetric spaces

Research Project

Project/Area Number 20K14310
Research Category

Grant-in-Aid for Early-Career Scientists

Allocation TypeMulti-year Fund
Review Section Basic Section 11020:Geometry-related
Research InstitutionHiroshima University

Principal Investigator

Okuda Takayuki  広島大学, 先進理工系科学研究科(理), 准教授 (40725131)

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: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2022: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
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)
Keywords等質空間 / 対称空間 / 部分多様体 / 粗幾何学 / 不連続群 / 符号理論 / リーマン幾何 / 全測地的部分多様体 / 微分幾何 / リー代数
Outline of Research at the Start

各点で点対称と呼ばれる変換が定義されているリーマン多様体をリーマン対称空間という. リーマン対称空間は球面やグラスマン多様体, 双曲空間などを例として含んでおり, 微分幾何学において重要な研究対象である. また全測地的部分多様体とは測地線の概念を一般化したものである. 「真直ぐなものを考える」という意味で, 全測地的部分多様体は最も基本的な部分多様体のクラスの一つである.本研究課題ではディンキン指数と呼ばれる不変量を定義し, 応用することによりリーマン対称空間内の部分多様体の分類問題に取り組むものである.

Outline of Final Research Achievements

Through this research, we successfully defined a natural number called the split Dynkin index for all totally geodesic embeddings between Riemannian symmetric spaces using the theory of Lie algebras. This correspondence generalizes the concept known as the Dynkin index for Lie algebra homomorphisms between complex simple Lie algebras and is considered an important concept for understanding the relationships between Riemannian symmetric spaces. We also developed a method to calculate the corresponding split Dynkin index for each embedding using the concept of complexification. Additionally, during the course of this research, the relationship between discontinuous groups on homogeneous spaces and coarse geometry has been elucidated.
These results are currently being prepared for submission as a journal paper.

Academic Significance and Societal Importance of the Research Achievements

リーマン対称空間と呼ばれる性質を持つ空間は幾何学において基本的かつ重要な研究対象である. 本研究はそれらの間の関係性を理解するためのものである. 本研究においてはリーマン対称空間の間に全測地的はめ込みという関係性が与えられたとき, それをある尺度において自然数で評価する手法を開発できた. この手法を用いて今後リーマン対称空間の関係性をより深く理解することが可能となった.

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

    (22 results)

All 2024 2023 2022 2020 Other

All Journal Article (5 results) (of which Int'l Joint Research: 2 results,  Peer Reviewed: 4 results,  Open Access: 2 results) Presentation (13 results) (of which Int'l Joint Research: 3 results,  Invited: 11 results) Remarks (3 results) Funded Workshop (1 results)

  • [Journal Article] A proof of Kobayashi's properness criterion from a viewpoint of metric geometry2024

    • Author(s)
      Kento Ogawa, Takayuki Okuda
    • Journal Title

      To appear in Progress in Mathematics, Symmetry in Geometry and Analysis---Festscrhift for Toshiyuki Kobayashi (tentative)

      Volume: -

    • Related Report
      2023 Annual Research Report
    • Peer Reviewed
  • [Journal Article] 等質空間上の固有な群作用と符号理論の関係について2023

    • Author(s)
      奥田隆幸
    • Journal Title

      代数的組合せ論シンポジウム報告集

      Volume: 39

    • Related Report
      2023 Annual Research Report
    • Open Access
  • [Journal Article] Explicit construction of exact unitary designs2022

    • Author(s)
      Bannai Eiichi、Nakata Yoshifumi、Okuda Takayuki、Zhao Da
    • Journal Title

      Advances in Mathematics

      Volume: 405 Pages: 108457-108457

    • DOI

      10.1016/j.aim.2022.108457

    • Related Report
      2022 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] On the spectrum and linear programming bound for hypergraphs2022

    • Author(s)
      Sebastian M. Cioaba, Jack H. Koolen, Masato Mimura, Hiroshi Nozaki, and Takayuki Okuda
    • Journal Title

      European Journal of Combinatorics

      Volume: 104 Pages: 103535-103535

    • DOI

      10.1016/j.ejc.2022.103535

    • Related Report
      2022 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] A commutativity condition for subsets in quandles -- a generalization of antipodal subsets2022

    • Author(s)
      Akira Kubo, Mika Nagashiki, Takayuki Okuda, Hiroshi Tamaru
    • Journal Title

      Differential Geometry and Global Analysis: In Honor of Tadashi Nagano

      Volume: -

    • Related Report
      2022 Research-status Report
    • Peer Reviewed
  • [Presentation] 等質空間上の固有な群作用と符号理論の関係について2023

    • Author(s)
      奥田 隆幸
    • Organizer
      第39回代数的組合せ論シンポジウム
    • Related Report
      2023 Annual Research Report
    • Invited
  • [Presentation] 等質空間上の固有な群作用と符号理論2023

    • Author(s)
      奥田隆幸
    • Organizer
      Japanese Conference on Combinatorics and its Applications 2023
    • Related Report
      2023 Annual Research Report
    • Invited
  • [Presentation] Coarse geometry and Kobayashi's properness criterion2023

    • Author(s)
      Takayuki Okuda
    • Organizer
      The 8th China-Japan Geometry conference
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Kobayashi's properness criterion and Coarse geometry2023

    • Author(s)
      Takayuki Okuda
    • Organizer
      7th Tunisian-Japanese Conference, Geometric and Harmonic Analysis on Homogeneous Spaces and Applications, in Honor of Professor Toshiyuki Kobayashi
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] デザインの解析的一般化について 2023年11月25日2023

    • Author(s)
      奥田隆幸
    • Organizer
      研究集会 「実験計画法と関連する組合せ構造および統計教育」
    • Related Report
      2023 Annual Research Report
    • Invited
  • [Presentation] Kobayashi's properness criterion and Coarse geometry2023

    • Author(s)
      奥田隆幸
    • Organizer
      第7回幾何学的群論ワークショップ
    • Related Report
      2023 Annual Research Report
    • Invited
  • [Presentation] 等質空間上の固有な作用について2023

    • Author(s)
      奥田隆幸
    • Organizer
      広島・岡山 代数学セミナー
    • Related Report
      2022 Research-status Report
    • Invited
  • [Presentation] Split Dynkin indices for homomorphisms between real simple Lie algebras2022

    • Author(s)
      奥田隆幸
    • Organizer
      2022年度RIMS共同研究(公開型)「表現論とその周辺分野における諸問題」
    • Related Report
      2022 Research-status Report
  • [Presentation] (t,m,s)-nets and profinite association schemes2022

    • Author(s)
      梶浦大起, 松本眞, 小川健翔, 奥田隆幸 (講演は奥田)
    • Organizer
      トポロジーとコンピュータ 2022
    • Related Report
      2022 Research-status Report
    • Invited
  • [Presentation] Totally geodesic immersions of direct products of two-spheres in compact symmetric spaces2022

    • Author(s)
      Takayuki Okuda
    • Organizer
      Geometry of symmetric spaces and group actions
    • Related Report
      2021 Research-status Report
    • Int'l Joint Research
  • [Presentation] Representation theory and combinatorics on compact homogeneous spaces2022

    • Author(s)
      奥田隆幸
    • Organizer
      Branched Coverings, Degenerations, and Related Topics
    • Related Report
      2021 Research-status Report
    • Invited
  • [Presentation] Kobayashi's properness criterion and totally geodesic submanifolds in locally symmetric spaces2020

    • Author(s)
      奥田隆幸
    • Organizer
      東京大学 Lie群論・表現論セミナー, トポロジー火曜セミナー(合同開催)
    • Related Report
      2020 Research-status Report
    • Invited
  • [Presentation] 対称R空間の大対蹠集合に定まる距離推移グラフ構造2020

    • Author(s)
      奥田隆幸
    • Organizer
      筑波大学 微分幾何学セミナー
    • Related Report
      2020 Research-status Report
    • Invited
  • [Remarks] research map (奥田隆幸)

    • URL

      https://researchmap.jp/takayuki_okuda

    • Related Report
      2023 Annual Research Report
  • [Remarks] reserachmap (Takayuki Okuda)

    • URL

      https://researchmap.jp/takayuki_okuda/

    • Related Report
      2021 Research-status Report
  • [Remarks] research map: 奥田隆幸

    • URL

      https://researchmap.jp/takayuki_okuda

    • Related Report
      2020 Research-status Report
  • [Funded Workshop] Geometry, Analysis, and Representation Theory of Lie Groups In honour of Prof. Toshiyuki Kobayashi's birthday2022

    • Related Report
      2022 Research-status Report

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

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