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Asymptotic analysis of quasilinear ordinary differential equations and its application to partial differential equations

Research Project

Project/Area Number 21K03307
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 12020:Mathematical analysis-related
Research InstitutionGifu University

Principal Investigator

Usami Hiroyuki  岐阜大学, 工学部, 教授 (90192509)

Project Period (FY) 2021-04-01 – 2024-03-31
Project Status Completed (Fiscal Year 2023)
Budget Amount *help
¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2023: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2022: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2021: ¥260,000 (Direct Cost: ¥200,000、Indirect Cost: ¥60,000)
Keywords漸近挙動 / 正値解 / 半分線形常微分方程式 / 準線形常微分方程式 / 準線形微分方程式 / 漸近形 / 常微分方程式 / 準線形
Outline of Research at the Start

多くの自然現象・社会現象が微分方程式を用いて定式化される.よって,常微分方程式の解の振舞いを数学的に考察することは種々の現象の本質的理解のために重要である.本研究では,重要な常微分方程式の解が,時刻が限りなく大きくなっていくときにどのような様相を呈するかを考察する.扱う方程式は定常状態を表す球対称な楕円型方程式や生態学・社会科学等に現れるロトカ・ヴォルテラ型方程式やランチェスター型方程式などである.
本研究の関連テーマで毎年度1回ほど関係者と研究集会を開催予定である.また,状況が許せば海外での国際会議等に赴き,関連分野の海外研究者と交流し,本研究の成果を広く発表する予定でもある.

Outline of Final Research Achievements

Mainly, asymptotic theory of solutions of quasilinear ordinary differential equations were investigated. More precisely, the following themes have been studied: 1. To find the asymptotic forms of perturbed half-linear ordinary differential equations with constant coefficients; 2. To find the asymptotic forms of positive solutions of super-homogeneous, quasilinear ordinary differential equations with critical coefficients; 3. To establish necessary and/or sufficient conditions for higher order quasilinear ordinary differential equations to have singular solutions; 4. To establish necessary and/or sufficient conditions for higher order quasilinear ordinary differential equations to have Kneser solutions.

Academic Significance and Societal Importance of the Research Achievements

1. 主テーマである半分線形方程式は線形方程式の一般化にあたる.研究手法等も線形方程式に対するそれの一般化にあたるであろう.数学理論がどのように普遍化・一般化されていくのかをこの研究を通じて俯瞰することができるであろう.
2.自然現象・社会現象を記述する数理モデルは,第一段階としては「線形近似」という見方で定式化されることが多い.しかし,より詳細にみると,本質的に非線形性になっているということもある.この研究ではそのような現象を数学的に解析する手法をいくつか提案している.

Report

(4 results)
  • 2023 Annual Research Report   Final Research Report ( PDF )
  • 2022 Research-status Report
  • 2021 Research-status Report
  • Research Products

    (14 results)

All 2024 2023 2022 2021

All Journal Article (7 results) (of which Int'l Joint Research: 2 results,  Peer Reviewed: 7 results,  Open Access: 2 results) Presentation (7 results) (of which Int'l Joint Research: 1 results)

  • [Journal Article] Asymptotic forms of solutions of half-linear ordinary differential equations with integrable perturbations2023

    • Author(s)
      Sokea Luey and Hiroyuki Usami
    • Journal Title

      Hiroshima Math. J.

      Volume: 53 Pages: 171-189

    • Related Report
      2023 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Existence of rapidly decaying positive solutions of quasilinear ordinary differential equations with arbitrary nonlinearities2023

    • Author(s)
      Hiroyuki Usami
    • Journal Title

      Mem. Differential Equations Math. Phys.

      Volume: 90 Pages: 111-119

    • Related Report
      2023 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] On the existence and asymptotic behavior of solutions of half-linear ordinary differential equations2022

    • Author(s)
      Manabu Naito and Hiroyuki Usami
    • Journal Title

      J. Differential Equations

      Volume: 318

    • Related Report
      2022 Research-status Report 2021 Research-status Report
    • Peer Reviewed
  • [Journal Article] Kneser solutions of higher-order quasilinear ordinary differential equations2022

    • Author(s)
      Manabu Naito and Hiroyuki Usami
    • Journal Title

      Funkcial. Ekvac.

      Volume: 65

    • Related Report
      2022 Research-status Report
    • Peer Reviewed
  • [Journal Article] Singular strongly increasing solutions of higher-order quasilinear ordinary differential equations2021

    • Author(s)
      Manabu Naito and Hiroyuki Usami
    • Journal Title

      Mem. Differ. Equ. Math. Phys.

      Volume: 84 Pages: 99-112

    • Related Report
      2021 Research-status Report
    • Peer Reviewed
  • [Journal Article] Application of generalised Riccati equations to analysis of asymptotic forms of solutions of perturbed half-linear ordinary differential equations2021

    • Author(s)
      Sokea Luey and Hiroyuki Usami
    • Journal Title

      Int. J. Dyn. Syst. Differ. Equ.

      Volume: 11 Pages: 378-390

    • Related Report
      2021 Research-status Report
    • Peer Reviewed
  • [Journal Article] Asymptotic forms of solutions of perturbed half-linear ordinary differential equations2021

    • Author(s)
      Sokea Luey and Hiroyuki Usami
    • Journal Title

      Arch. Math. (Brno)

      Volume: 57 Pages: 27-39

    • Related Report
      2021 Research-status Report
    • Peer Reviewed
  • [Presentation] 射的問題について2024

    • Author(s)
      宇佐美広介・前田貴之
    • Organizer
      日本数学会年会
    • Related Report
      2023 Annual Research Report
  • [Presentation] 半分線形常微分方程式の解の漸近挙動について2023

    • Author(s)
      宇佐美広介・内藤学
    • Organizer
      日本数学会秋季総合分科会
    • Related Report
      2023 Annual Research Report
  • [Presentation] 非線形項に単調性等を仮定しない常微分方程式の正値解の非存在定理について2023

    • Author(s)
      宇佐美広介
    • Organizer
      RIMS共同研究「精密解析による非線形問題の新展開」
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research
  • [Presentation] 非線形項に単調性等を仮定しない常微分方程式の正値解の非存在定理について2023

    • Author(s)
      宇佐美 広介
    • Organizer
      日本数学会 年会
    • Related Report
      2022 Research-status Report
  • [Presentation] 摂動された半分線形常微分方程式の解の存在と漸近挙動について2022

    • Author(s)
      宇佐美 広介,内藤 学
    • Organizer
      日本数学会 秋季総合分科会
    • Related Report
      2022 Research-status Report
  • [Presentation] 摂動された半分線形常微分方程式の解の存在と漸近挙動について2022

    • Author(s)
      宇佐美 広介, 内藤 学
    • Organizer
      日本数学会 年会
    • Related Report
      2021 Research-status Report
  • [Presentation] Asymptotic forms of solutions of perturbed half-linear ordinary differential equations2021

    • Author(s)
      宇佐美 広介, ソケア ルイ
    • Organizer
      日本数学会 秋季総合分科会
    • Related Report
      2021 Research-status Report

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Published: 2021-04-28   Modified: 2025-01-30  

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