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2003 Fiscal Year Final Research Report Summary

The norm structure of Banach spaces and its application.

Research Project

Project/Area Number 14540160
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Basic analysis
Research InstitutionNIIGATA UNIVERSITY

Principal Investigator

SAITO Kichi-suke  NIIGATA UNIVERSITY, Faculty of Science, Professor, 理学部, 教授 (30018949)

Co-Investigator(Kenkyū-buntansha) HATORI Osamu  NIIGATA UNIVERSITY, Faculty of Science, Professor, 理学部, 教授 (70156363)
TAKAHASHI Yasuji  Okayama Prefectural University, Faculty of Computer Science and System Engineering, Professor, 情報工学部, 教授 (30001853)
KATO Mikio  Kyushu Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (50090551)
ASANO Kazuo  NIIGATA UNIVERSITY, Faculty of Science, Lecturer, 理学部, 講師 (80000876)
SUZUKI Tomonari  Kyushu Institute of Technology, Faculty of Engineering, Associate Professor, 工学部, 助教授 (00303173)
Project Period (FY) 2002 – 2003
KeywordsBanach space / uniform convex / strict convex / von Neumann-Jordan constant / James constant
Research Abstract

The study of Banach space theory is an important and useful object in the every branch of Mathematics and has many applications. In this Research, we study the rotundity and the nonsquareness of unit balls of Banach spaces. In particular, we attempt to study the absolute norms of C^n.
(1)At first, we defined the 4-direct sum of two Banach spaces and we showed the necessary and sufficient conditions that the space is strictly convex(resp.uniform convex).
(2)We proved the necessary and sufficient conditions that the absolute norm on C^n is smooth.
(3)We have the formulae of the James constant of absolute normed space on R^2 and we apply the Lorentz space.
(4)We study the uniform nonsquareness of C^n. We showed the uniform nonsquareness of 4-direct sum of two Banach spaces.
In the near future, we study the geometrical structure of the infinite dimensional Banach spaces, in particular, Schatten p-class operators c_p, Orliz space, noncommutativeL^p-space and so on.

  • Research Products

    (24 results)

All Other

All Publications (24 results)

  • [Publications] Kichi-Suke Saito: "Uniform convexity of 4-direct sums of Banach spaces"J.Mathematical Analysis and Applications. 277. 1-11 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Mikio Kato: "On 4-direct sums of Banach spaces and convexity"J.Australian Mathematical Society. 75. 413-422 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ken-ichi Mitani: "Smoothness of absolute norms on C^n"J.Convex Analysis. 10. 89-107 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ken-ichi Mitani: "The James constant of absolute norms on R^2"J.Nonlinear and Convex Analysis. 4. 399-410 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Osamu Hatori: "Chracterizations and automatic linearity for ring homomorphisms on algebras of functions"Contemp.Math.. 328. 201-215 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tomonari Suzuki: "Convergence theorems to common fixed points for infinite families of Nonexpansive mappings in strict convex Banach spaces"Nihonkai Math.J.. 14. 43-54 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tomonari Suzuki: "On strong convergence to common fixed points of nonexpansive semigruops in Hilbert spaces"Proc.Amer.Math.Soc.. 131. 2133-2136 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tomonari Suzuki: "On Downing-Kirk's theorem"J.Mathematical Analysis and Applications. 286. 453-458 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yasuji Takahashi: "Strict convexity of absolute norms on C and direct sums of Banach spaces"J.Inequalities and Applications. 7. 179-186 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yasuji Takahashi: "On sharp uniform convexity, smoothness and strong type, cotype inequalities"J.Nonlinear and Convex Analysis. 3. 267-281 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Sin-ei Takahashi: "A note on a class of Banach algebra-valued polynomials"International J.Math.Math.Sci.. 32. 189-192 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tomonari Suzuki: "Strong convergence theorem to common fixed points of two nonexpansive mapping in general Banach spaces"J.Nonlinear and Convex Analysis. 3. 381-391 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Kichi-Suke Saito: "Uniform convexity of 4-direct sums of Banach spaces"J.Math.Anal.Appl.. 277. 1-11 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Mikio Kato: "On 4-direct sums of Banach spaces and convexity"J.Australian Mathematical Society. 75. 413-422 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Ken-ichi Mitani: "Smoothness of absolute norms on C^n"J.Convex Analysis. 10. 89-107 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Ken-ichi Mitani: "The James constant of absolute norms on R^2"J.Nonlinear and Convex Analysis. 4. 399-410 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Osamu Hatori: "hracterizations and automatic linearity for ring homomorphisms on algebras of functions"Contemp.Math.. 328. 201-215 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Tomonari Suzuki: "Convergence theorems to common fixed points for infinite families of Nonexpansive mappings in strict convex Banach spaces"Nihonkai Math.J.. 14. 43-54 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Tomonari Suzuki: "On strong convergence to common fixed points of nonexpansive semigruops in Hilbert spaces"Prop.Amer.Math.Soc.. 131. 2133-2136 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Tomonari Suzuki: "On Downing-Kirk's theorem"J.Math.Anal.Appl.. 286. 453-458 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yasuji Takahashi: "Strict convexity of absolute norms on C^2 and direct sums of Banach spaces"J.Inequalities and Applications. 7. 179-186 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yasuji Takahashi: "On sharp uniform convexity, smoothness and strong type, cotype inequalities"J.Nonlinear and Convex Analysis. 3. 267-281 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Sin-ei Takahashi: "A note on a class of Banach algebra-valued polynomials"International J.Math.Math.Sci.. 32. 189-192 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Tomonari Suzuki: "Strong convergence theorem to common fixed points of two nonexpansive mapping in general Banach spaces"J.Nonlinear and Convex Analysis. 3. 381-391 (2002)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2005-04-19  

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