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2013 年度 実施状況報告書

Geometry of geodesics of Riemannian and Finsler manifolds

研究課題

研究課題/領域番号 25400075
研究種目

基盤研究(C)

研究機関東海大学

研究代表者

SABAU Vasile Sor  東海大学, 札幌教養教育センター, 准教授 (80364280)

研究期間 (年度) 2013-04-01 – 2016-03-31
キーワードRiemannian manifolds / Finsler manifolds / cut locus / convex functions / Busemann functions / topological cylinder / level sets' structure / differentiability
研究概要

In this year, we have revised and finalized the construction of a Riemannian metric on the Sphere and a Finsler metric of Randers type whose cut locus is a fractal. This is a joint research with Professor J. Itoh from Kumamoto University.These metrics are not smooth metrics, but only k-class metrics. We have summarized these findings in a paper and have submitted already to an international journal.
In a joint research with Professor K. Shiohama from Fukuoka University we have studied the geometrical properties of convex functions defined on Finsler manifolds. Moreover, the structure of the level sets of convex functions as well as the topological restrictions of the existence of convex functions on Finsler manifolds were thoroughly investigated. These results were summarized in a research paper and submitted to an international journal.
Moreover, I have started the study of Busemann functions on a Finsler manifold and obtain first results about the differentiability of this kind of functions as well as about the structure of the co points set. I intend to summarize these findings in a paper and submit it to an international journal in the near future.

現在までの達成度 (区分)
現在までの達成度 (区分)

2: おおむね順調に進展している

理由

We consider that the research is progressing smoothly according to the research plan. Actually, I have interchanged one topic, I proposed to study the Busemann functions in 2013 and the properties of convex functions on Finsler manifolds in 2014, but I studied the properties of convex functions on Finsler manifolds in 2013 and leave the study of the Busemann functions for 2014.
The reason of doing this is because the definition of convex functions on Finsler manifolds was more complex as initially thought and complete classification of the topological restrictions on the topology of the base manifold took a lot of time. However, this interchange of topics is beneficial for the present research because it provides general results about the behavior of convex functions on Finsler manifolds, results that can be applied to the case of Busemann functions on some Finsler manifolds of non-negative flag curvature.

今後の研究の推進方策

I intend to stick with the research plan described in the application form.
More specifically, in this year I intend to study the properties of cut locus of a Finsler manifold and compare these with the similar results for Riemannian manifolds.
Moreover, I will focus in the study of geometrical properties of the Busemann functions on Finsler manifolds and the structure of the co-points set. We expect that this research will give similar results as in the Riemannian case. However, the fact that the Finslerian geodesics are not reversible and that the Finslerian distance function is not symmetric needs a special treatment. Even the final results are similar with the Riemannian counterpart, the arguments are quite different.

次年度の研究費の使用計画

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  • 研究成果

    (6件)

すべて 2014 2013

すべて 雑誌論文 (1件) (うち査読あり 1件) 学会発表 (5件) (うち招待講演 2件)

  • [雑誌論文] Kropina metrics and Zermelo navigation on Riemannian manifolds2013

    • 著者名/発表者名
      R. Yoshikawa, S. V. Sabau
    • 雑誌名

      Geometriae dedicata

      巻: July ページ: 1-23

    • DOI

      10.1007/s10711-013-9892-8

    • 査読あり
  • [学会発表] Some convexity related topics in Finsler geometry. Applications2014

    • 著者名/発表者名
      Sorin V. Sabau
    • 学会等名
      The Fourth TKU-KMITL Joint Symposium on Mathematics and Applied Mathematics
    • 発表場所
      東海大学、湘南キャンパス(平塚市神奈川県)
    • 年月日
      20140319-20140320
  • [学会発表] Generalized Finsler structures on closed 3-manifolds2014

    • 著者名/発表者名
      Sorin V. Sabau
    • 学会等名
      日本数学会(春学会)
    • 発表場所
      学習院大学、東京
    • 年月日
      20140315-20140318
  • [学会発表] Weighted Quasi-Metrics and Finsler metrics2013

    • 著者名/発表者名
      Sorin V. Sabau
    • 学会等名
      The 48-th Symposium on Finsler Geometry
    • 発表場所
      東海大学、札幌キャンパス
    • 年月日
      20130915-20130917
  • [学会発表] Quasi-metrics. Geometry of sequence comparison2013

    • 著者名/発表者名
      Sorin V. Sabau
    • 学会等名
      Asia Symposium on Engineering and Information
    • 発表場所
      Landmark Bangkok Hotel, Bangkok (タイ)
    • 年月日
      20130727-20130729
    • 招待講演
  • [学会発表] On the behavior of geodesics on a Finsler space2013

    • 著者名/発表者名
      Sorin V. Sabau
    • 学会等名
      2013 International Symposium on Riemann-Finsler geometry
    • 発表場所
      Henan Normal University (中国)
    • 年月日
      20130507-20130513
    • 招待講演

URL: 

公開日: 2015-05-28  

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