• Title/Summary/Keyword: Hilbert space.

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GENERALIZED (C, r)-HANKEL OPERATOR AND (R, r)-HANKEL OPERATOR ON GENERAL HILBERT SPACES

  • Jyoti Bhola;Bhawna Gupta
    • Communications of the Korean Mathematical Society
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    • v.38 no.3
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    • pp.821-835
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    • 2023
  • Hankel operators and their variants have abundant applications in numerous fields. For a non-zero complex number r, the r-Hankel operators on a Hilbert space 𝓗 define a class of one such variant. This article introduces and explores some properties of two other variants of Hankel operators namely kth-order (C, r)-Hankel operators and kth-order (R, r)-Hankel operators (k ≥ 2) which are closely related to r-Hankel operators in such a way that a kth-order (C, r)-Hankel matrix is formed from rk-Hankel matrix on deleting every consecutive (k - 1) columns after the first column and a kth-order (R, rk)-Hankel matrix is formed from r-Hankel matrix if after the first column, every consecutive (k - 1) columns are deleted. For |r| ≠ 1, the characterizations for the boundedness of these operators are also completely investigated. Finally, an appropriate approach is also presented to extend these matrices to two-way infinite matrices.

STRONG CONVERGENCE OF A MODIFIED ISHIKAWA ITERATIVE ALGORITHM FOR LIPSCHITZ PSEUDOCONTRACTIVE MAPPINGS

  • Osilike, M.O.;Isiogugu, F.O.;Attah, F.U.
    • Journal of applied mathematics & informatics
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    • v.31 no.3_4
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    • pp.565-575
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    • 2013
  • Let H be a real Hilbert space and let T : H ${\rightarrow}$ H be a Lipschitz pseudocontractive mapping. We introduce a modified Ishikawa iterative algorithm and prove that if $F(T)=\{x{\in}H:Tx=x\}{\neq}{\emptyset}$, then our proposed iterative algorithm converges strongly to a fixed point of T. No compactness assumption is imposed on T and no further requirement is imposed on F(T).