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Symmetry and deformation of spherical tiling

Research Project

Project/Area Number 16K05247
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Research Field Foundations of mathematics/Applied mathematics
Research InstitutionTohoku University

Principal Investigator

Akama Yohji  東北大学, 理学研究科, 准教授 (30272454)

Project Period (FY) 2016-04-01 – 2022-03-31
Project Status Completed (Fiscal Year 2021)
Budget Amount *help
¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2019: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2018: ¥390,000 (Direct Cost: ¥300,000、Indirect Cost: ¥90,000)
Fiscal Year 2017: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2016: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
Keywordsタイリング / 合同な多角形 / 曲率 / グラフ / 離散曲率 / 球面タイリング / コーシーの腕補題 / 合同な等辺5角形による球面タイリング / 放電論法 / Forman曲率 / タイル推移的 / 球面的多面体的曲面 / pseudo-double wheel / 1-skeleton / 組合せ曲率 / テーラー展開 / 正多角形的球面多面体的表面 / ヤコビアン / ギャップ / 精度保証計算 / タイル推移性 / 対称性 / 離散幾何 / 幾何構造
Outline of Final Research Achievements

By Euler's law, the spherical tilings by congruent polygons are only by triangles, quadrangles, and pentagons. In particular, a spherical tiling by congruent equilateral pentagons is exactly a pentagonal subdivision of a tiling, an earthmap tiling or a flip modification of an earthmap tiling. Moreover, we introduce a new technique similar to Cauchy's arm lemma for polyhedra. Because the area of the sphere is finite and lines on the sphere necessarily intersect, the research on the classification of the spherical tilings by congruent polygons is of recent, and combinatorially hard. As an abstract approach to this problem, we find out not only the symmetry of the tilings, but also the combinatorial curvature of graph which corresponds to Gauss curvature of surfaces.

Academic Significance and Societal Importance of the Research Achievements

球面は平面の幾何的直観を相対化するが、球面は曲がりの度合いが正の一定である一方で平面のそれは0の一定であり、球面と平面のタイリング(重なりなく隙間なく埋めつくすこと)は、装飾として供され、数学的物理的関連が認められつつある。合同な多角形による平面タイリングの分類は伝統があり困難であるが、球面は面積が有限で球面では異なる「直線」は交差するため、合同な多角形による球面タイリングの分類研究は新しく、組み合わせ論的に困難であるが、そこで、計算機の援用の必要性を我々は示唆した。この問題への抽象的接近法として、曲面のガウス曲率に対応する、グラフの組み合わせ曲率の理論を見出した。

Report

(7 results)
  • 2021 Annual Research Report   Final Research Report ( PDF )
  • 2020 Research-status Report
  • 2019 Research-status Report
  • 2018 Research-status Report
  • 2017 Research-status Report
  • 2016 Research-status Report
  • Research Products

    (20 results)

All 2022 2021 2019 2018 2017 2016 Other

All Int'l Joint Research (9 results) Journal Article (3 results) (of which Peer Reviewed: 3 results,  Open Access: 1 results) Presentation (5 results) (of which Int'l Joint Research: 3 results) Remarks (3 results)

  • [Int'l Joint Research] 復旦大学/香港科学技術大学(中国)

    • Related Report
      2020 Research-status Report
  • [Int'l Joint Research] 復旦大学/上海数学中心(中国)

    • Related Report
      2019 Research-status Report
  • [Int'l Joint Research] 復旦大学/福州大学(中国)

    • Related Report
      2018 Research-status Report
  • [Int'l Joint Research] 香港科学技術大学/復旦大学(中国)

    • Related Report
      2017 Research-status Report
  • [Int'l Joint Research] Rdjer Boskovic Institute(クロアチア)

    • Related Report
      2017 Research-status Report
  • [Int'l Joint Research] Ruder Boskovic Institute(クロアチア)

    • Related Report
      2016 Research-status Report
  • [Int'l Joint Research] 香港科学技術大学(中国)

    • Related Report
      2016 Research-status Report
  • [Int'l Joint Research] Sobolev Institute of Mathematics(ロシア連邦)

    • Related Report
      2016 Research-status Report
  • [Int'l Joint Research] Gent university(ベルギー)

    • Related Report
      2016 Research-status Report
  • [Journal Article] Tilings of the sphere by congruent pentagons III: Edge combination a52022

    • Author(s)
      Akama Yohji、Wang Erxiao、Yan Min
    • Journal Title

      Advances in Mathematics

      Volume: 394 Pages: 107881-107881

    • DOI

      10.1016/j.aim.2021.107881

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed
  • [Journal Article] A curvature notion for planar graphs stable under planar duality2021

    • Author(s)
      Akama Yohji、Hua Bobo、Su Yanhui、Wang Lili
    • Journal Title

      Advances in Mathematics

      Volume: 385 Pages: 107731-107731

    • DOI

      10.1016/j.aim.2021.107731

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Classification of spherical tilings by congruent quadrangles over pseudo-double wheels (II) - the isohedral case2019

    • Author(s)
      Yohji Akama
    • Journal Title

      Hiroshima Mathematical Journal

      Volume: 49

    • Related Report
      2018 Research-status Report
    • Peer Reviewed / Open Access
  • [Presentation] Tiling of the Sphere by Congruent Polygons2021

    • Author(s)
      赤間陽二
    • Organizer
      The 23rd Thailand-Japan Conference on Discrete and Computational Geometry, Graphs, and Games
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Computational Study on Combinatorial curvatures and Forman curvatures of planar graphs2019

    • Author(s)
      赤間 陽二
    • Organizer
      復旦大学数学学術報告
    • Related Report
      2019 Research-status Report
  • [Presentation] 組み合わせ曲率と正多角形による多面体的surface2018

    • Author(s)
      赤間 陽二
    • Organizer
      2018年度応用数学合同研究集会
    • Related Report
      2018 Research-status Report
  • [Presentation] Deza's last problems2017

    • Author(s)
      Yohji Akama
    • Organizer
      Franco-Japanese Days on Combinatorics and Optimization 2017
    • Related Report
      2017 Research-status Report
    • Int'l Joint Research
  • [Presentation] Spherical tilings by congruent 4-gons on Archimedean dual skeletons2016

    • Author(s)
      Yohji Akama
    • Organizer
      The 12th Annual Meeting of the International Academy of Mathematical Chemistry (IAMC) and the 2016 International Conference on Mathematical Chemistry (ICMC 2016)
    • Place of Presentation
      Nankai University, Tsianjin, China
    • Related Report
      2016 Research-status Report
    • Int'l Joint Research
  • [Remarks] http://www.math.tohoku.ac.jp/~akama/stcq

    • Related Report
      2020 Research-status Report
  • [Remarks] Classification of spherical monohedral tilings

    • URL

      http://www.math.tohoku.ac.jp/~akama/stcq/

    • Related Report
      2019 Research-status Report
  • [Remarks] https://www.math.tohoku.ac.jp/~akama/stcq

    • Related Report
      2018 Research-status Report

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Published: 2016-04-21   Modified: 2023-01-30  

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