Takayama, Masahiro

写真a

Affiliation

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

Position

Assistant Professor/Senior Assistant Professor
Scopus Paper Info  
Paper Count: 15 Citation Count: 59 h-index: 6

Click to view the Scopus page. The data was downloaded from Scopus API in March 15, 2026, via http://api.elsevier.com and http://www.scopus.com .

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Profile Summary 【 Display / hide 】

  • 高山正宏です。専門は数学で、偏微分方程式について研究をしています。特に退化双曲型方程式といった退化型の方程式に対する初期境界値問題に興味をもっています。現在は主に、吊り下げられた紐の運動についての研究を行っています。

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Career 【 Display / hide 】

  • 2000.04
    -
    2001.03

    大阪大学大学院理学研究科, 教務補佐員

  • 2000.04
    -
    2001.03

    大阪電気通信大学工学部第1部, 非常勤講師

  • 2001.04
    -
    2007.03

    慶應義塾大学理工学部数理科学科, 助手

  • 2007.04
    -
    Present

    慶應義塾大学理工学部数理科学科, 助教

  • 2009.04
    -
    2018.03

    明治大学理工学部, 非常勤講師

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Academic Background 【 Display / hide 】

  • 1989.04
    -
    1993.03

    Kanazawa University, 理学部, 数学科

    University, Graduated

  • 1993.04
    -
    1995.03

    Osaka University, 理学研究科 博士前期課程, 数学専攻

    Graduate School, Completed, Master's course

  • 1995.04
    -
    2000.03

    Osaka University, 理学研究科 博士後期課程, 数学専攻

    Graduate School, Completed, Doctoral course

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Academic Degrees 【 Display / hide 】

  • 博士（理学）, Osaka University, Coursework, 2000.03

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Matters concerning Career Achievements 【 Display / hide 】

  • 2001.04
    -
    2025.03

    数理科学科セミナーノート編集委員

  • 2017.04
    -
    2025.03

    数理科学科図書委員

  • 2025.04
    -
    Present

    数理科学科学習指導副主任

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Research Areas 【 Display / hide 】

  • Natural Science / Basic analysis (偏微分方程式)

  • Natural Science / Mathematical analysis (偏微分方程式)

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Research Keywords 【 Display / hide 】

  • degenerate hyperbolic equation, motion of a string

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Research Themes 【 Display / hide 】

  • 紐の運動の研究, 

    2006
    -
    Present

    　View Summary

    吊り下げられた紐の運動に対する初期境界値問題の適切性について研究を行っている。

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Papers 【 Display / hide 】

  • TIME-GLOBAL SOLVABILITY OF THE VLASOV–POISSON SYSTEM AROUND THE TRAVELING WAVES

    Suzuki M., Takayama M., Zhang K.Z.

    Kinetic and Related Models 19   35 - 63 2026.02

    ISSN  19375093

    　View Summary

    We consider the 1D Vlasov–Poisson system on the real line, and establish the time-global solvability for arbitrarily large initial data f<inf>±</inf><sup>0</sup> . We assume that the support of the difference between the initial data f<inf>±</inf><sup>0</sup> and f<inf>±</inf><sup>∗,</sup><sup>0</sup> is compact in the phase space, where f<inf>±</inf><sup>∗,</sup><sup>0</sup> is the initial value of traveling waves of the 1D Vlasov–Poisson system.

  • Nonlinear stability and instability of plasma boundary layers

    Suzuki M., Takayama M., Zhang K.Z.

    Physica D Nonlinear Phenomena 481 2025.11

    ISSN  01672789

    　View Summary

    We investigate the formation of a plasma boundary layer (sheath) by considering the Vlasov–Poisson system on a half space with the completely absorbing boundary condition. In Suzuki and Takayama (2023), the solvability of the stationary problem is studied. In this paper, we study the nonlinear stability and instability of these stationary solutions of the Vlasov–Poisson system.

  • WELL-POSEDNESS OF THE INITIAL BOUNDARY VALUE PROBLEM FOR DEGENERATE HYPERBOLIC SYSTEMS WITH A LOCALIZED TERM AND ITS APPLICATION TO THE LINEARIZED SYSTEM FOR THE MOTION OF AN INEXTENSIBLE HANGING STRING

    Iguchi T., Takayama M.

    Osaka Journal of Mathematics 62 ( 4 ) 507 - 538 2025.10

    ISSN  00306126

    　View Summary

    Motivated by an analysis on the well-posedness of the initial boundary value problem for the motion of an inextensible hanging string, we first consider an initial boundary value problem for one-dimensional degenerate hyperbolic systems with a localized term and show its well-posedness in weighted Sobolev spaces. We then consider the linearized system for the motion of an inextensible hanging string. Well-posedness of its initial boundary value problem is demonstrated as an application of the result obtained in the first part.

  • Traveling waves of the Vlasov–Poisson system

    Suzuki M., Takayama M., Zhang K.Z.

    Journal of Differential Equations 428   230 - 290 2025.05

    ISSN  00220396

    　View Summary

    We consider the Vlasov–Poisson system describing a two-species plasma with spatial dimension 1 and the velocity variable in Rn. We find the necessary and sufficient conditions for the existence of solitary waves, shock waves, and wave trains of the system, respectively. To this end, we need to investigate solutions that are not BGK waves. Furthermore, we classify completely in all possible cases whether or not the traveling wave is unique. The uniqueness varies according to each traveling wave when we exclude the variant caused by translation. For the solitary wave, there are both cases that it is unique and nonunique. The shock wave is always unique. No wave train is unique.

  • Traveling waves of the Vlasov-Poisson system

    Masahiro Suzuki, Masahiro Takayama, Katherine Zhiyuan Zhang

    Journal of Differential Equations 428   230 - 290 2025

    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 】

  • Correction to: A priori estimates for solutions to equations of motion of an inextensible hanging string (Mathematische Annalen, (2024), 390, 2, (1919-1971), 10.1007/s00208-023-02786-5)

    Iguchi T., Takayama M.

    Mathematische Annalen 391 ( 3 ) 4847 - 4848 2024

    ISSN  00255831

    　View Summary

    The article “A priori estimates for solutions to equations of motion of an inextensible hanging string”, written by Tatsuo Iguchi and Masahiro Takayama, was originally published Online First without Open Access. After publication in volume 390, issue 2, pages 1919–1971 the author decided to opt for Open Choice and to make the article an Open Access publication. Therefore, the copyright of the article has been changed to © The Author(s) 2024 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0. The original article has been corrected.

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Presentations 【 Display / hide 】

  • 吊り下げられた紐の運動に対する初期境界値問題の適切性

    高山正宏, 井口達雄

    [Domestic presentation]  日本数学会（早稲田大学） (早稲田大学) , 

    2025.03
    , 

    Oral presentation (general)

  • 吊り下げられた紐の運動に対する解のアプリオリ評価

    高山正宏

    [Domestic presentation]  数学と現象 in 宮崎 2024 (宮崎大学) (宮崎大学) , 

    2024.11
    , 

    Oral presentation (invited, special)

  • 局所項をもつ退化双曲系に対する初期境界値問題の適切性

    高山正宏, 井口達雄

    [Domestic presentation]  日本数学会（大阪大学） (大阪大学) , 

    2024.09
    , 

    Oral presentation (general)

  • 吊り下げられた紐の運動に対する線形化問題の適切性

    高山正宏, 井口達雄

    [Domestic presentation]  日本数学会（大阪大学）, 

    2024.09
    , 

    Oral presentation (general)

  • A priori estimates for solutions to equations of motion of an inextensible hanging string

    Takayama Masahiro

    [International presentation]  流体と気体の数学解析（京都大学益川ホール） (京都大学益川ホール) , 

    2024.06
    , 

    Oral presentation (invited, special)

    　View Summary

    吊り下げられた伸びない紐の運動方程式に対する初期境界値問題について講演した。解の正則性の指数 m が４以上として、解のアプリオリ評価について発表した。

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Courses Taught 【 Display / hide 】

  • SPECIAL EXERCISE IN MATHEMATICAL SCIENCE

    2025

  • OFF-CAMPUS WORK-STUDY PROGRAM

    2025

  • MATHEMATICS 1B

    2025

  • MATHEMATICS 1A

    2025

  • INDEPENDENT STUDY ON FUNDAMENTAL SCIENCE AND TECHNOLOGY

    2025

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Courses Previously Taught 【 Display / hide 】

  • 数理解析同演習

    Keio University

    2018.04
    -
    2019.03
    , 

    Spring Semester, Undergraduate (specialized), Seminar, Lecturer outside of Keio

  • 関数方程式第１同演習

    Keio University

    2018.04
    -
    2019.03
    , 

    Autumn Semester, Undergraduate (specialized), Seminar, Lecturer outside of Keio

  • 実解析第１同演習

    Keio University

    2018.04
    -
    2019.03
    , 

    Spring Semester, Undergraduate (specialized), Seminar, Lecturer outside of Keio

  • 数理解析同演習

    Keio University

    2017.04
    -
    2018.03
    , 

    Spring Semester, Undergraduate (specialized), Seminar, Lecturer outside of Keio

  • 関数論第１同演習

    Keio University

    2017.04
    -
    2018.03
    , 

    Autumn Semester, Undergraduate (specialized), Seminar, Lecturer outside of Keio

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Memberships in Academic Societies 【 Display / hide 】

  • 日本数学会, 

    1996.04
    -
    Present
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