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Towards a deeper understanding of K-stability

Research Project

Project/Area Number 20K14321
Research Category

Grant-in-Aid for Early-Career Scientists

Allocation TypeMulti-year Fund
Review Section Basic Section 11020:Geometry-related
Research InstitutionTokyo University of Science

Principal Investigator

Saito Shunsuke  東京理科大学, 理学部第一部数学科, 助教 (10846752)

Project Period (FY) 2020-04-01 – 2024-03-31
Project Status Completed (Fiscal Year 2023)
Budget Amount *help
¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2022: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2021: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2020: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
KeywordsK安定性 / 漸近的Chow安定性 / トーリック多様体 / 一様相対Ding安定性 / 満渕定数 / 相対K安定性 / 超平面切断 / Fano多様体 / Calabi夢多様体 / 相対安定性 / Ding安定性 / 強K安定性 / 一様K安定性
Outline of Research at the Start

ケーラーアインシュタイン計量、スカラー曲率一定ケーラー計量や端的ケーラー計量などの標準ケーラー計量の存在問題と関連して現れた偏極多様体の幾何学的不変式論的安定性について研究を行う。目指すところは次の二点である。
(1) 複数あるK安定性の強化概念や漸近的Chow安定性などの相互関係を明確に理解する。
(2) トーリック多様体など対称性の高いものでしか定義できていなかった安定性概念を一般の多様体に拡張しその性質を調べる。

Outline of Final Research Achievements

I have obtained the following results related to the stability of polarized varieties: (1)For a polarized toric surface on which the obstructions of asymptotic Chow semistability vanish, K-polystability implies asymptotic Chow polystability; (2)A new definition of relative Chow stability by means of a quantization of extremal vector fields has been given; (3)Examples of relatively Ding unstable toric Fano manifolds which are uniformly relatively K-stable for any polarization have been given for all dimensions greater than or equal to three; (4)Errors in Yotsutani-Zhou's classification of relative K-stability of smooth toric Fano 3-folds have been found; (5)K-stability of hyperplane sections of Segre varieties for anticanonical polarization have been determined completely.

Academic Significance and Societal Importance of the Research Achievements

偏極代数多様体は数学において基本的な研究対象であり、その分類を行う上で標準計量の存在・非存在あるいは安定性・不安定性といった情報は重要な役割を担う。本研究課題の研究成果は、当該研究分野の中心的な問題について決定的な解答を与えるといった類のものではないが、トーリック多様体や超平面切断などの具体的な代数多様体の分類に関して素朴だが興味深い問題をいくつか提示できたという点で発展性や意義のあるものだと言える。

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

    (6 results)

All 2024 2023 2021

All Journal Article (3 results) (of which Int'l Joint Research: 1 results,  Peer Reviewed: 3 results) Presentation (3 results) (of which Int'l Joint Research: 1 results,  Invited: 3 results)

  • [Journal Article] Examples of relatively Ding unstable Calabi dream manifolds2024

    • Author(s)
      Yasufumi Nitta and Shunsuke Saito
    • Journal Title

      Proceedings of the American Mathematical Society

      Volume: 152 Pages: 553-558

    • DOI

      10.1090/proc/16643

    • Related Report
      2023 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Relative Ding and K-stability of toric Fano manifolds in low dimensions2023

    • Author(s)
      Yasufumi Nitta, Shunsuke Saito and Naoto Yotsutani
    • Journal Title

      European Journal of Mathematics

      Volume: 9 Issue: 2

    • DOI

      10.1007/s40879-023-00617-0

    • Related Report
      2022 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] A note on Yotsutani-Zhou condition for relative K-instability2023

    • Author(s)
      Nitta Yasufumi, Saito Shunsuke
    • Journal Title

      Kodai Mathematical Journal

      Volume: 46 Pages: 219-227

    • Related Report
      2022 Research-status Report
    • Peer Reviewed
  • [Presentation] 偏極トーリック多様体の相対安定性・不安定性の多面体的な十分条件について2021

    • Author(s)
      齋藤俊輔
    • Organizer
      神楽坂微分幾何学セミナー
    • Related Report
      2021 Research-status Report
    • Invited
  • [Presentation] 偏極トーリック曲面の漸近的Chow安定性について2021

    • Author(s)
      齋藤俊輔
    • Organizer
      第68回幾何学シンポジウム
    • Related Report
      2021 Research-status Report
    • Invited
  • [Presentation] Algebro-geometric stabilities for polarized toric varieties2021

    • Author(s)
      Shunsuke Saito
    • Organizer
      The 27th Symposium on Complex Geometry (Kanazawa) 2021
    • Related Report
      2021 Research-status Report
    • Int'l Joint Research / Invited

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

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