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A study on nonlinear problems using convex analysis and fixed point theory

Research Project

Project/Area Number 25800094
Research Category

Grant-in-Aid for Young Scientists (B)

Allocation TypeMulti-year Fund
Research Field Foundations of mathematics/Applied mathematics
Research InstitutionTokai University (2015-2016)
Oita University (2013-2014)

Principal Investigator

KOHSAKA Fumiaki  東海大学, 理学部, 准教授 (20434003)

Project Period (FY) 2013-04-01 – 2017-03-31
Project Status Completed (Fiscal Year 2016)
Budget Amount *help
¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2016: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2015: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2014: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2013: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Keywords非線形解析学 / 非線形問題 / 不動点理論 / 凸関数 / 単調作用素 / ヒルベルト空間 / バナッハ空間 / 測地的距離空間 / Bregman distance / 不動点定理 / 不動点近似 / アダマール空間 / 完備CAT(1)空間 / 近接点法 / CAT(1)空間 / 不動点 / 球面幾何 / 凸解析 / 関数解析 / 非線形作用素 / 集合値写像
Outline of Final Research Achievements

In this research, using convex analysis for convex functions and convex sets and fixed point theory for nonlinear operators, we study the existence and approximation of solutions to several nonlinear problems. In particular, we obtain several results on the existence and approximation of fixed points of nonlinear operators in infinite dimensional linear spaces such as Hilbert spaces and Banach spaces. Applying the obtained results to minimization problems for convex functions and zero point problems for monotone operators, we obtain existence and convergence theorems for such problems. We also obtain some important results on the relation between convex minimization problems and fixed point problems in geodesic metric spaces with no linear structure.

Report

(5 results)
  • 2016 Annual Research Report   Final Research Report ( PDF )
  • 2015 Research-status Report
  • 2014 Research-status Report
  • 2013 Research-status Report
  • Research Products

    (31 results)

All 2017 2016 2015 2014 2013 Other

All Journal Article (14 results) (of which Peer Reviewed: 11 results,  Open Access: 8 results,  Acknowledgement Compliant: 6 results) Presentation (17 results) (of which Int'l Joint Research: 5 results,  Invited: 4 results)

  • [Journal Article] Existence and approximation of fixed points of Chatterjea mappings with Bregman distances2017

    • Author(s)
      Fumiaki Kohsaka and Tomonari Suzuki
    • Journal Title

      Linear and Nonlinear Analysis

      Volume: 3

    • Related Report
      2016 Annual Research Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] The proximal point algorithm in geodesic spaces with curvature bounded above2017

    • Author(s)
      Yasunori Kimura and Fumiaki Kohsaka
    • Journal Title

      Linear and Nonlinear Analysis

      Volume: 3

    • Related Report
      2016 Annual Research Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] Two modified proximal point algorithms for convex functions in Hadamard spaces2016

    • Author(s)
      Yasunori Kimura and Fumiaki Kohsaka
    • Journal Title

      Linear and Nonlinear Analysis

      Volume: 2

    • Related Report
      2016 Annual Research Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] Spherically nonspreading mappings in geodesic spaces with curvature bounded above by one2016

    • Author(s)
      Y. Kimura and F. Kohsaka
    • Journal Title

      Journal of Fixed Point Theory and Applications

      Volume: 18 Issue: 1 Pages: 93-115

    • DOI

      10.1007/s11784-015-0267-7

    • Related Report
      2015 Research-status Report
    • Peer Reviewed
  • [Journal Article] Existence and approximation of common fixed points of two hybrid mappings in Hilbert spaces2015

    • Author(s)
      Fumiaki Kohsaka
    • Journal Title

      Journal of Nonlinear and Convex Analysis

      Volume: 16 Pages: 2193-2205

    • Related Report
      2015 Research-status Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] バナッハ空間におけるfirmly nonexpansive-like写像に対する不動点近似2015

    • Author(s)
      高阪史明
    • Journal Title

      京都大学数理解析研究所講究録

      Volume: 1963 Pages: 170-177

    • Related Report
      2015 Research-status Report
    • Open Access
  • [Journal Article] Weak convergence theorem for a sequence of quasinonexpansive type mappings2015

    • Author(s)
      Fumiaki Kohsaka
    • Journal Title

      Proceedings of the 8th International Conference on Nonlinear Analysis and Convex Analysis

      Volume: - Pages: 289-300

    • Related Report
      2014 Research-status Report
    • Peer Reviewed
  • [Journal Article] Ray's theorem revisited: a fixed point free firmly nonexpansive mapping in Hilbert spaces2015

    • Author(s)
      Fumiaki Kohsaka
    • Journal Title

      Journal of Inequalities and Applications

      Volume: 2015 Issue: 1 Pages: 1-3

    • DOI

      10.1186/s13660-015-0606-7

    • Related Report
      2014 Research-status Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] Strongly relatively nonexpansive sequences generated by firmly nonexpansive-like mappings2014

    • Author(s)
      Koji Aoyama, Fumiaki Kohsaka
    • Journal Title

      Fixed Point Theory and Applications

      Volume: 2014 Issue: 1 Pages: 1-13

    • DOI

      10.1186/1687-1812-2014-95

    • Related Report
      2014 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] An implicitly defined iterative sequence for monotone operators in Banach spaces2014

    • Author(s)
      Fumiaki Kohsaka
    • Journal Title

      Journal of Inequalities and Applications

      Volume: 2014 Issue: 1 Pages: 1-9

    • DOI

      10.1186/1029-242x-2014-181

    • Related Report
      2014 Research-status Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] Viscosity ap- proximation process for a sequence of quasi- nonexpansive mappings2014

    • Author(s)
      K. Aoyama and F. Kohsaka
    • Journal Title

      Fixed Point Theory and Applications

      Volume: 17 Issue: 1 Pages: 11-11

    • DOI

      10.1186/1687-1812-2014-17

    • Related Report
      2013 Research-status Report
    • Peer Reviewed
  • [Journal Article] Averaged sequences for nonspreading mappings in Banach spaces2014

    • Author(s)
      Fumiaki Kohsaka
    • Journal Title

      Proceedings of the International Symposium on Banach and Function Spaces IV

      Volume: - Pages: 313-323

    • Related Report
      2013 Research-status Report
    • Peer Reviewed
  • [Journal Article] ハイブリッド写像の不動点について2013

    • Author(s)
      高阪史明
    • Journal Title

      京都大学数理解析研究所講究録

      Volume: 1841 Pages: 77-85

    • Related Report
      2013 Research-status Report
  • [Journal Article] 集合値写像の零点問題と関連する不動点定理2013

    • Author(s)
      高阪史明
    • Journal Title

      京都大学数理解析研究所講究録

      Volume: 1852 Pages: 25-32

    • Related Report
      2013 Research-status Report
  • [Presentation] Minimizing convex functions in geodesic metric spaces with curvature bounded above2016

    • Author(s)
      Fumiaki Kohsaka
    • Organizer
      The International Conference on New Trends in Optimization and Variational Analysis for Applications
    • Place of Presentation
      Quy Nhon University, Quy Nhon, Vietnam
    • Year and Date
      2016-12-08
    • Related Report
      2016 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] アダマール空間における凸関数の最小点近似2016

    • Author(s)
      高阪史明
    • Organizer
      日本数学会2016年度秋季総合分科会
    • Place of Presentation
      関西大学千里山キャンパス (大阪府)
    • Year and Date
      2016-09-17
    • Related Report
      2016 Annual Research Report
  • [Presentation] Common fixed points of two commutative hybrid mappings in Hilbert spaces2016

    • Author(s)
      高阪史明
    • Organizer
      非線形解析学と凸解析学の研究
    • Place of Presentation
      京都大学数理解析研究所 (京都府)
    • Year and Date
      2016-09-01
    • Related Report
      2016 Annual Research Report
  • [Presentation] Spherically nonspreading mappings in geodesic metric spaces with curvature bounded above2016

    • Author(s)
      Fumiaki Kohsaka
    • Organizer
      The 5th Asian Conference on Nonlinear Analysis and Optimization
    • Place of Presentation
      Toki Messe, Niigata, Japan
    • Year and Date
      2016-08-05
    • Related Report
      2016 Annual Research Report
    • Int'l Joint Research
  • [Presentation] 凸最小化問題と関連する非線形写像とその不動点について2016

    • Author(s)
      高阪史明
    • Organizer
      数理経済学会2016年度定例セミナー
    • Place of Presentation
      法政大学市ヶ谷キャンパス (東京都)
    • Year and Date
      2016-06-10
    • Related Report
      2016 Annual Research Report
    • Invited
  • [Presentation] Existence and approximation of minimizers of convex functions in geodesic metric spaces2016

    • Author(s)
      Fumiaki Kohsaka
    • Organizer
      The 9th Asian Conference on Fixed Point Theory and Optimization
    • Place of Presentation
      King Mongkut's University of Technology Thonburi, Bangkok, Thailand
    • Year and Date
      2016-05-19
    • Related Report
      2016 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] バナッハ空間における極大単調作用素に対する陰的な零点近似列の強収束性2016

    • Author(s)
      高阪史明
    • Organizer
      日本数学会2016年度年会
    • Place of Presentation
      筑波大学筑波キャンパス (茨城県つくば市)
    • Year and Date
      2016-03-18
    • Related Report
      2015 Research-status Report
  • [Presentation] An implicitly defined iterative sequence for maximal monotone operators in Banach spaces2015

    • Author(s)
      Fumiaki Kohsaka
    • Organizer
      VII Symposium on Nonlinear Analysis
    • Place of Presentation
      Nicolaus Copernicus University, Torun, Poland
    • Year and Date
      2015-09-17
    • Related Report
      2015 Research-status Report
    • Int'l Joint Research
  • [Presentation] Asymptotic behavior of averaged sequences for nonspreading mappings in Banach spaces2015

    • Author(s)
      Fumiaki Kohsaka
    • Organizer
      The Fifth International Symposium on Banach and Function Spaces 2015
    • Place of Presentation
      Kyushu Institute of Technology, Kitakyushu, Japan
    • Year and Date
      2015-09-02
    • Related Report
      2015 Research-status Report
    • Int'l Joint Research
  • [Presentation] Mean convergence theorems for pointwise convergent sequences of hybrid mappings2015

    • Author(s)
      Fumiaki Kohsaka
    • Organizer
      The Ninth International Conference on Nonlinear Analysis and Convex Analysis
    • Place of Presentation
      Rimkok Resort Hotel, Chiang Rai, Thailand
    • Year and Date
      2015-01-21
    • Related Report
      2014 Research-status Report
  • [Presentation] Fixed point approximation for firmly nonexpansive-like mappings in Banach spaces2014

    • Author(s)
      高阪史明
    • Organizer
      非線形解析学と凸解析学の研究
    • Place of Presentation
      京都大学数理解析研究所 (京都府京都市)
    • Year and Date
      2014-08-21
    • Related Report
      2014 Research-status Report
  • [Presentation] Finding fixed points of firmly nonexpansive-like mappings in Banach spaces2014

    • Author(s)
      Fumiaki Kohsaka
    • Organizer
      The International Congress in Honour of Professor Ravi P. Agarwal
    • Place of Presentation
      Uludag University, Bursa, Turkey
    • Year and Date
      2014-06-24
    • Related Report
      2014 Research-status Report
  • [Presentation] Unbounded sets and nonexistence of fixed points in Banach spaces

    • Author(s)
      Fumiaki Kohsaka
    • Organizer
      The International Conference Anatolian Communications in Nonlinear Analysis
    • Place of Presentation
      Abant Izzet Baysal University, Bolu, Turkey
    • Related Report
      2013 Research-status Report
  • [Presentation] On firmly nonexpansive type mappings in Banach spaces

    • Author(s)
      Fumiaki Kohsaka
    • Organizer
      The Eighth International Conference on Nonlinear Analysis and Convex Analysis
    • Place of Presentation
      Hirosaki University, Hirosaki, Japan
    • Related Report
      2013 Research-status Report
  • [Presentation] Strong convergence theorem for a strongly relatively nonexpansive sequence of mappings

    • Author(s)
      Fumiaki Kohsaka
    • Organizer
      The International Conference on Nonlinear Analysis and Optimization
    • Place of Presentation
      National Sun Yat-sen University, Kaohsiung, Taiwan
    • Related Report
      2013 Research-status Report
    • Invited
  • [Presentation] 二変数関数の鞍点と非線形写像の不動点

    • Author(s)
      高阪史明
    • Organizer
      日本数学会2013年度秋季総合分科会
    • Place of Presentation
      愛媛大学城北キャンパス
    • Related Report
      2013 Research-status Report
  • [Presentation] ヒルベルト空間におけるハイブリッド写像に対する不動点問題

    • Author(s)
      高阪史明
    • Organizer
      Miniworkshop on Analysis at Kagurazaka
    • Place of Presentation
      東京理科大学神楽坂キャンパス
    • Related Report
      2013 Research-status Report

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Published: 2014-07-25   Modified: 2019-07-29  

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