OTA Katsuhiro

写真a

Affiliation

Faculty of Science and Technology, Department of Mathematics （Yagami）

Position

Professor

External Links
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Career 【 Display / hide 】

  • 1989.04
    -
    1993.03

    慶應義塾大学（理工学部数理科学科） ,助手

  • 1993.04
    -
    1997.03

    慶應義塾大学（理工学部数理科学科） ,専任講師

  • 1993.04
    -
    2010.09

    明治大学理工学部（数学A，確率，線形代数など）, 非常勤講師

  • 1997.04
    -
    Present

    慶應義塾大学（理工学部数理科学科） ,助教授

  • 2011.04
    -
    2011.09

    明治大学理工学部　非常勤講師

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Academic Background 【 Display / hide 】

  • 1984.03

    The University of Tokyo, Faculty of Science, 情報科学科

    University, Graduated

  • 1986.03

    The University of Tokyo, Graduate School, Division of Science, 情報科学専門課程

    Graduate School, Completed, Master's course

  • 1989.03

    The University of Tokyo, Graduate School, Division of Science, 情報科学専門課程

    Graduate School, Completed, Doctoral course

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Academic Degrees 【 Display / hide 】

  • 理学　, The University of Tokyo, 1989.03

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Research Areas 【 Display / hide 】

  • Natural Science / Basic mathematics

  • Natural Science / Applied mathematics and statistics

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Research Keywords 【 Display / hide 】

  • Graph Theory

  • Combinatorics

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Books 【 Display / hide 】

  • グラフ理論

    R. Diestel著, シュプリンガー・フェアラーク東京, 2000.10

    　View Summary

    根上生也との共訳

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Papers 【 Display / hide 】

  • Color degree sum conditions for properly colored spanning trees in edge-colored graphs

    Kano M., Maezawa S.i., Ota K., Tsugaki M., Yashima T.

    Discrete Mathematics （Discrete Mathematics)  343 （ 11 ）  2020.11

    ISSN  0012365X

    　View Summary

    For a vertex v of an edge-colored graph, the color degree of v is the number of colors appeared in edges incident with v. An edge-colored graph is called properly colored if no two adjacent edges have the same color. In this paper, we prove that if the minimum color degree sum of two adjacent vertices of an edge-colored connected graph G is at least |G|, then G has a properly colored spanning tree. This is a generalization of the result proved by Cheng, Kano and Wang. We also show the sharpness of this lower bound of the color degree sum.

  • Edge proximity conditions for extendability in planar triangulations

    Jun Fujisawa and Katsuhiro Ota

    Journal of Graph Theory 80 （ 1 ） 1 - 11 2015.09

    Research paper (scientific journal), Joint Work, Accepted

  • Hadwiger's conjecture for degree sequences

    Guantao Chen and Katsuhiro Ota

    Journal of Combinatorial Theory, Series B 114   247 - 249 2015.09

    Research paper (scientific journal), Joint Work, Accepted

  • Disjoint chorded cycles of the same length

    Guantao Chen, Ronald J. Gould, Kazuhide Hirohata, Katsuhiro Ota and Songling Shan

    SIAM Journal on Discrete Mathematics 29 （ 2 ） 1030 - 1041 2015

    Research paper (scientific journal), Joint Work, Accepted

  • Maximal cycles in graphs of large girth

    Jun Fujisawa and Katsuhiro Ota

    SUT Journal of Mathematics 50 （ 2 ） 427 - 438 2014

    Research paper (scientific journal), Joint Work, Accepted

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Papers, etc., Registered in KOARA 【 Display / hide 】

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Reviews, Commentaries, etc. 【 Display / hide 】

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Presentations 【 Display / hide 】

  • Small theta subgraphs in sparse graphs

    2017 Joint Mathematical Meetings, AMS Special Session on Topics in Graph Theory (Atlanta, Georgia, USA) , 

    2017.01
    , 

    Oral presentation (general)

  • Vertex-disjoint even cycles of the same length

    Y. Egawa, S. Fujita, K. Ota, T. Sakuma

    ACCOTA 2016, International Workshop on Combinatorial and Computational Aspects of Optimization, Topology and Algebra (Los Cabos, Mexico) , 

    2016.11
    , 

    Oral presentation (general)

  • グラフが同じ長さの点素な偶閉路を含むための次数条件

    太田克弘, 江川嘉美, 藤田慎也, 佐久間雅

    日本数学会2015年度秋季総合分科会 (京都産業大学) , 

    2015.09
    , 

    Oral presentation (general), 日本数学会

  • Vertex-disjoint isomorphic theta subgraphs

    S. Fujita, K. Ota, T. Sakuma

    2014 SIAM Conference on Discrete Mathematics, Minisymposium: Cycles and Paths (Minneaoplis, Minesota) , 

    2014.06
    , 

    Oral presentation (general)

  • Vertex-disjoint isomorphic theta subgraphs

    S. Fujita, K. Ota, T. Sakuma

    The 3rd Taiwan-Japan Conference on Combinatorics and its Applications (National Chiayi University, Taiwan) , 

    2014.03
    , 

    Oral presentation (general)

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

  • グラフの大域構造に着目した極値問題の研究

    2022.04
    -
    2026.03

    MEXT,JSPS, Grant-in-Aid for Scientific Research, 基盤研究(C), Principal investigator

  • 疎なグラフに対する極値グラフ理論の展開

    2016.04
    -
    2020.03

    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Principal investigator

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Works 【 Display / hide 】

  • 理工学部１年生授業科目「数学２・数学４」の講義テキストの作成

    OTA KATSUHIRO

    2014.04
    -
    2015.03
    , 

    Other, Joint

  • 数理科学科２年生授業科目「数理科学基礎第２」の講義テキスト・演習問題の作成

    OTA KATSUHIRO

    2003.09
    -
    2005.02
    , 

    Other, Joint

  • 理工学部１年生授業科目「数学Ａ１，Ｂ１」の講義テキストの作成

    OTA KATSUHIRO

    　
    , 

    Other, Joint

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Courses Taught 【 Display / hide 】

  • SURVEY ON INFORMATICS

    2024

  • MATHEMATICS 2B

    2024

  • MATHEMATICS 2A

    2024

  • LIBERAL ARTS AND SCIENCES SEMINAR 2

    2024

  • INDEPENDENT STUDY ON FUNDAMENTAL SCIENCE AND TECHNOLOGY

    2024

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Memberships in Academic Societies 【 Display / hide 】

  • 日本数学会, 

    1986
    -
    Present

  • 日本数学会, 

    2004.10
    -
    2006.09

  • 日本数学会, 

    2010.06
    -
    2014.05

  • 日本数学会, 

    2008.06
    -
    2010.05
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Committee Experiences 【 Display / hide 】

  • 2004.10
    -
    2006.09

    Committee Member, 日本数学会

  • 2010.06
    -
    2014.05

    広報委員長, 日本数学会

  • 2008.06
    -
    2010.05

    広報委員会委員, 日本数学会

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