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A study on invariants that guarantee the existence of cycles and trees

Research Project

Project/Area Number 24740074
Research Category

Grant-in-Aid for Young Scientists (B)

Allocation TypeMulti-year Fund
Research Field General mathematics (including Probability theory/Statistical mathematics)
Research InstitutionKinki University

Principal Investigator

YAMASHITA Tomoki  近畿大学, 理工学部, 准教授 (10410458)

Project Period (FY) 2012-04-01 – 2016-03-31
Project Status Completed (Fiscal Year 2015)
Budget Amount *help
¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2015: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2014: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2013: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2012: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Keywordsハミルトン閉路 / 次数和条件 / 全域木 / 閉路
Outline of Final Research Achievements

In 2008, Ozeki and I discovered a rule of a degree sum condition with the order, the connectivity and the independence number of a graph for the existence of a hamiltonian cycle. The rule is that the lower bound on the degree condition is an arithmetic progression with common difference of ``the independence number - 1''.
We proved that the rule holds for degree sum condition of two, three or four vertices, and conjectured the rule holds for degree sum condition of at least five vertices. Moreover, we posed a similar conjecture for the circumference. For these two conjectures, we settled the conjecture on hamiltonicity, and the conjecture on circumference for a degree sum condition of four vertices.

Report

(5 results)
  • 2015 Annual Research Report   Final Research Report ( PDF )
  • 2014 Research-status Report
  • 2013 Research-status Report
  • 2012 Research-status Report
  • Research Products

    (16 results)

All 2015 2014 2013 2012 Other

All Int'l Joint Research (1 results) Journal Article (9 results) (of which Int'l Joint Research: 1 results,  Peer Reviewed: 9 results,  Acknowledgement Compliant: 3 results,  Open Access: 1 results) Presentation (6 results)

  • [Int'l Joint Research] Vanderbilt University(米国)

    • Related Report
      2015 Annual Research Report
  • [Journal Article] Perfect matchings avoiding prescribed edges in a star-free graph2015

    • Author(s)
      Yoshimi Egawa, Jun Fujisawa, Michael D. Plummer, Akira Saito and Tomoki Yamashita
    • Journal Title

      Discrete Mathematics

      Volume: 339 Issue: 12 Pages: 2260-2274

    • DOI

      10.1016/j.disc.2015.05.014

    • Related Report
      2015 Annual Research Report
    • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Spanning k-trees of Bipartite Graphs2015

    • Author(s)
      Mikio Kano, K.Ozeki, K.Suzuki, M.Tsugaki and T.Yamashita
    • Journal Title

      Electron. J. Combin.

      Volume: 22

    • Related Report
      2014 Research-status Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] Closure and spanning k-trees2014

    • Author(s)
      R. Matsubara, M. Tsugaki, and T.Yamashita
    • Journal Title

      Graphs and Combinatorics

      Volume: 30 Issue: 4 Pages: 957-962

    • DOI

      10.1007/s00373-013-1314-z

    • Related Report
      2014 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Degree sum conditions for the circumference of 4-connected graphs2014

    • Author(s)
      S.Chiba, M.Tsugaki and T.Yamashita
    • Journal Title

      Discrete Math.

      Volume: 333 Pages: 66-83

    • DOI

      10.1016/j.disc.2014.06.012

    • Related Report
      2014 Research-status Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] Degree sum conditions for cyclability in bipartite graphs2013

    • Author(s)
      H.Okamura and T.Yamashita
    • Journal Title

      Graphs Combin.

      Volume: 29 Issue: 4 Pages: 1077-1085

    • DOI

      10.1007/s00373-012-1148-0

    • Related Report
      2013 Research-status Report
    • Peer Reviewed
  • [Journal Article] Spanning Caterpillars Having at Most k Leaves2013

    • Author(s)
      M.Kano, T.Yamashita and Z.Yan
    • Journal Title

      Computational Geometry and Graphs (Lecture Notes in Computer Science)

      Volume: 8296 Pages: 95-100

    • DOI

      10.1007/978-3-642-45281-9_9

    • ISBN
      9783642452802, 9783642452819
    • Related Report
      2013 Research-status Report
    • Peer Reviewed
  • [Journal Article] Spanning trees with a bounded number of leaves in a claw-free graphs2013

    • Author(s)
      H. Matsuda, K. Ozeki, T. Yamashita
    • Journal Title

      Graphs and Combinatorics

      Volume: (掲載決定) Issue: 2 Pages: 429-437

    • DOI

      10.1007/s00373-012-1277-5

    • Related Report
      2013 Research-status Report
    • Peer Reviewed
  • [Journal Article] Long cycles in unbalanced bipartite graphs2012

    • Author(s)
      S. Chiba, J. Fujisawa, M. Tsugaki and T. Yamashita
    • Journal Title

      Discrete Mathematics

      Volume: 312 Issue: 11 Pages: 1857-1862

    • DOI

      10.1016/j.disc.2012.02.019

    • Related Report
      2012 Research-status Report
    • Peer Reviewed
  • [Journal Article] Length of Longest Cycles in a Graph Whose Relative Length is at Least Two2012

    • Author(s)
      K.Ozeki, T.Yamashita
    • Journal Title

      Graphs and Combinatorics

      Volume: (掲載決定) Issue: 6 Pages: 859-868

    • DOI

      10.1007/s00373-011-1078-2

    • Related Report
      2012 Research-status Report
    • Peer Reviewed
  • [Presentation] 閉路や木が存在するための次数和条件2015

    • Author(s)
      山下 登茂紀
    • Organizer
      平成 27 年度 RIMS 共同研究「デザイン、符号、 グラフおよびその周辺」
    • Place of Presentation
      京都大学数理解析研究所
    • Year and Date
      2015-07-10
    • Related Report
      2015 Annual Research Report
  • [Presentation] ハミルトン閉路が存在するための次数和条件2014

    • Author(s)
      千葉 周也, 古谷 倫貴, 小関 健太, 津垣 正男, 山下 登茂紀
    • Organizer
      離散数学とその応用研究集会
    • Place of Presentation
      新潟総合テレビゆめディア(新潟県)
    • Year and Date
      2014-08-21
    • Related Report
      2014 Research-status Report
  • [Presentation] ハミルトン閉路が存在するための次数和条件2014

    • Author(s)
      山下 登茂紀
    • Organizer
      田澤新成先生ご退職記念 関西グラフ理論研究集会
    • Place of Presentation
      近畿大学総合社会学部
    • Related Report
      2013 Research-status Report
  • [Presentation] Degree sum conditions concerning the connectivity and the independence number2012

    • Author(s)
      S.Chiba, M.Tsugaki and T.Yamashita
    • Organizer
      Cycles in Graphs
    • Place of Presentation
      Vanderbilt University (Nashville, United States of America)
    • Related Report
      2012 Research-status Report
  • [Presentation] ある数列問題と離散幾何への応用2012

    • Author(s)
      中本 敦浩,小田 芳彰,山下 登茂紀,渡辺 守
    • Organizer
      離散数学1日研究集会
    • Place of Presentation
      東京理科大学 (東京)
    • Related Report
      2012 Research-status Report
  • [Presentation] グラフの不変量と閉路の存在について2012

    • Author(s)
      山下 登茂紀
    • Organizer
      日本応用数理学会2012年度年会
    • Place of Presentation
      稚内全日空ホテル(稚内)
    • Related Report
      2012 Research-status Report

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Published: 2013-05-31   Modified: 2022-01-27  

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