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Structural analysis of graphs by degree conditions to the existence of cycles including specified elements

Research Project

Project/Area Number 19K03610
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 12030:Basic mathematics-related
Research InstitutionIbaraki National College of Technology

Principal Investigator

Hirohata Kazuhide  茨城工業高等専門学校, 国際創造工学科, 教授 (30321392)

Project Period (FY) 2019-04-01 – 2023-03-31
Project Status Completed (Fiscal Year 2022)
Budget Amount *help
¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
Fiscal Year 2021: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2020: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2019: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
KeywordsDiscrete Mathematics / Graph Theory / cycle / chord / chorded cycle / vertex-disjoint cycles / minimum degree sum / pancyclic graph / 離散数学 / グラフ理論 / 閉路 / 弦 / 弦付き閉路 / 点素な閉路 / 最小次数和 / 全閉路的グラフ / パンサイクリックグラフ
Outline of Research at the Start

グラフ理論の中で非常に重要な概念にグラフの閉路があり、古くからハミルトン閉路(グラフのすべての頂点を通る閉路)の存在や閉路の長さに関する研究が盛んに行われてきた。本研究では従来の閉路に関する研究をさらに発展させ、任意の頂点や辺などを指定し、それらを含む閉路の存在について、次数条件の見地から研究を行う。また、閉路上の非連続な2頂点を結ぶ「弦」とよばれる辺をもつ閉路に関する研究も行う。これらの閉路の存在が証明されれば、それらをもとに任意の指定要素を含む閉路によるグラフ分割問題に発展させることができ、グラフの構造がより明らかとなる。

Outline of Final Research Achievements

In Graph Theory, the studies of cycles are very important, and there have been studies regarding a Hamiltonian cycle which visits each vertex exactly once, and the length of cycles for a long time. In this study, we develop the former studies of cycles, and study the existence of multiple cycles, and cycles including any specified elements such as vertices or edges. In study duration, we obtained results on vertex-disjoint chorded cycles and chorded pancyclic graphs with any specified vertex or edge.

Academic Significance and Societal Importance of the Research Achievements

閉路によるグラフの分割問題は、グラフの因子問題(与えられたグラフに対して、ある特定の性質を満たす全域部分グラフの存在を示す問題)とも密接な関係があり、本研究で得られた結果を発展させ因子問題研究を行うことができる。また、閉路が弦を持つとき、偶数の長さを持つ閉路(偶閉路)の存在を示すことができ、グラフの構造がより明らかとなる。

Report

(5 results)
  • 2022 Annual Research Report   Final Research Report ( PDF )
  • 2021 Research-status Report
  • 2020 Research-status Report
  • 2019 Research-status Report
  • Research Products

    (9 results)

All 2022 2021 2020 Other

All Int'l Joint Research (2 results) Journal Article (2 results) (of which Int'l Joint Research: 2 results,  Peer Reviewed: 2 results,  Open Access: 1 results) Presentation (5 results)

  • [Int'l Joint Research] エモリー大学/テネシー大学/ケンタッキー大学(米国)

    • Related Report
      2020 Research-status Report
  • [Int'l Joint Research] エモリー大学(米国)

    • Related Report
      2019 Research-status Report
  • [Journal Article] On independent triples and vertex-disjoint chorded cycles in graphs2020

    • Author(s)
      Ronald J. Gould, Kazuhide Hirohata, Ariel Keller Rorabaugh
    • Journal Title

      Australasian Journal of Combinatorics

      Volume: 77(3) Pages: 355-372

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] On degree sum conditions and vertex-disjoint chorded cycles2020

    • Author(s)
      Bradley Elliott, Ronald J. Gould, Kazuhide Hirohata
    • Journal Title

      Graphs and Combinatorics

      Volume: 36(6) Issue: 6 Pages: 1927-1945

    • DOI

      10.1007/s00373-020-02227-z

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Presentation] Degree sum conditions for the existence of vertex-disjoint chorded cycles in a graph2022

    • Author(s)
      Kazuhide Hirohata, Bradley Elliott, Ronald J. Gould
    • Organizer
      2022 日本数学会年会 応用数学分科会
    • Related Report
      2021 Research-status Report
  • [Presentation] Vertex-disjoint chorded cycles and degree sum conditions2021

    • Author(s)
      Kazuhide Hirohata, Bradley Elliott, Ronald J. Gould
    • Organizer
      2021 応用数学合同研究集会
    • Related Report
      2021 Research-status Report
  • [Presentation] Vertex-disjoint chorded cycles and degree sum conditions2021

    • Author(s)
      Kazuhide Hirohata, Ronald J. Gould, Ariel K. Rorabaugh
    • Organizer
      2021 日本数学会秋季総合分科会
    • Related Report
      2021 Research-status Report
  • [Presentation] Vertex-disjoint chorded cycles and degree sum conditions2021

    • Author(s)
      Kazuhide Hirohata, Ronald J. Gould, Ariel K. Rorabaugh
    • Organizer
      Japanese Conference on Combinatorics and its Applications 2021
    • Related Report
      2021 Research-status Report
  • [Presentation] Vertex-disjoint chorded cycles and degree sum condition2020

    • Author(s)
      Ronald J. Gould, Kazuhide Hirohata, Ariel Keller Rorabaugh
    • Organizer
      日本数学会 秋季総合分科会
    • Related Report
      2020 Research-status Report

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Published: 2019-04-18   Modified: 2024-01-30  

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