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リッチ曲率が下に有界な空間のトポロジー安定性

研究課題

研究課題/領域番号 23KJ0204
研究種目

特別研究員奨励費

配分区分基金
応募区分国内
審査区分 小区分11020:幾何学関連
研究機関東北大学

研究代表者

PENG YUANLIN  東北大学, 理学研究科, 特別研究員(DC1)

研究期間 (年度) 2023-04-25 – 2026-03-31
研究課題ステータス 交付 (2023年度)
配分額 *注記
2,600千円 (直接経費: 2,600千円)
2025年度: 900千円 (直接経費: 900千円)
2024年度: 900千円 (直接経費: 900千円)
2023年度: 800千円 (直接経費: 800千円)
キーワードmetric geometry / RCD spaces / Green function / rigidity
研究開始時の研究の概要

Our research is intended to prove a topological stability theorem for a special class of metric measure spaces, namely $RCD(K,N)$ spaces which, roughly speaking, are metric measure spaces with Ricci curvature bounded below by $K$ and dimension bounded above by $N$ in some synthetic sense. Our desired result is that if an $RCD(K,N)$ space is similar to a Riemannian manifold (in mGH-sense), then we can deform the $RCD(K,N)$ space into the manifold with arbitrarily small deformation.

研究実績の概要

In the past academic year, the author focused on the analysis and geometry of RCD spaces.
As planned at the beginning of this project, the author has read the literature mentioned in the research plan. Besides, he also found some other recent results that might be useful. He believes there is some way to solve the problem hidden behind these results.
As for research acievements, the author and his supervisor, Prof. Honda, established some properties of Green functions on metric measure spaces with non-negative Ricci curvature, including a sharp gradient estimate, a rigidity theorem to cone, and the quantitative version of rigidity theorem. These results are helpful for further study of elliptic PDEs on RCD spaces.

現在までの達成度 (区分)
現在までの達成度 (区分)

1: 当初の計画以上に進展している

理由

In the plan proposed at the beginning of the project, the main purpose of the first year is to learn related work that might be helpful to prove the desired Laplacian comparison conjecture. The author has already read the literature listed in the research plan. And moreover, he also found some other directions that may work, for instance, some results defining the mean curvature of the boundary of subsets in RCD spaces using the isoperimetric property.
Besides, the author is also investigating along the direction of analysis and PDE. That is why he also focused on study of Green functions on RCD spaces. These published results can be regarded as byproducts of this project.

今後の研究の推進方策

As there are hopeful methods already come into the author's view, it is time to attack the main question, namely the Laplacian comparison conjecture. As observed by the author and his collaborators, the main difficulty is the analysis near the boundary. There are two possible directions. The first one is to get this result via methods of analysis and PDE. The key point of this way is to extend the space compactiblly with the boundary. This needs further regularity result of the boundary. The second one is to work more on the geometric aspect. And this way requires better definition and properties of the tensors, for instance, second fundamental form and mean cuvature, on the boundary. From the author's view, regularity of boundary is also needed here.

報告書

(1件)
  • 2023 実施状況報告書
  • 研究成果

    (2件)

すべて 2024 2023

すべて 雑誌論文 (1件) (うち国際共著 1件、 査読あり 1件) 学会発表 (1件) (うち国際学会 1件)

  • [雑誌論文] Sharp gradient estimate, rigidity and almost rigidity of Green functions on non-parabolic RCD (0, N) spaces2024

    • 著者名/発表者名
      Shouhei Honda, Yuanlin Peng
    • 雑誌名

      Proceedings of the Royal Society of Edinburgh Section A: Mathematics

      巻: First view ページ: 1-54

    • DOI

      10.1017/prm.2024.131

    • 関連する報告書
      2023 実施状況報告書
    • 査読あり / 国際共著
  • [学会発表] Almost rigidity of Green functions on RCD(0,N) spaces2023

    • 著者名/発表者名
      Yuanlin Peng
    • 学会等名
      Geometry & Probability 2023
    • 関連する報告書
      2023 実施状況報告書
    • 国際学会

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公開日: 2023-04-26   更新日: 2024-12-25  

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