Korovkin-type theorems on B(H) and their applications to function spaces

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Authors

  • Wolfram Bauer
  • V. B. Kiran Kumar
  • Rahul Rajan

Research Organisations

External Research Organisations

  • Cochin University of Science and Technology
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Details

Original languageEnglish
Pages (from-to)257-284
Number of pages28
JournalMonatshefte für Mathematik
Volume197
Issue number2
Early online date26 Apr 2021
Publication statusPublished - Feb 2022

Abstract

We prove Korovkin-type theorems in the setting of infinite dimensional Hilbert space operators. The classical Korovkin theorem unified several approximation processes. Also, the non-commutative versions of the theorem were obtained in various settings such as Banach algebras, C-algebras and lattices etc. The Korovkin-type theorem in the context of preconditioning large linear systems with Toeplitz structure can be found in the recent literature. In this article, we obtain a Korovkin-type theorem on B(H) which generalizes all such results in the recent literature. As an application of this result, we obtain Korovkin-type approximation for Toeplitz operators acting on various function spaces including Bergman space A2(D) , Fock space F2(C) etc. These results are closely related to the preconditioning problem for operator equations with Toeplitz structure on the unit disk D and on the whole complex plane C. It is worthwhile to notice that so far such results are available for Toeplitz operators on circle only. This also establishes the role of Korovkin-type approximation techniques on function spaces with certain oscillation property. To address the function theoretic questions using these operator theory tools will be an interesting area of further research.

Keywords

    Bergman space, Convergence in cluster sense, Fock space, Korovkin-type theorems, Preconditioner, Toeplitz operators

ASJC Scopus subject areas

Cite this

Korovkin-type theorems on B(H) and their applications to function spaces. / Bauer, Wolfram; Kumar, V. B. Kiran; Rajan, Rahul.
In: Monatshefte für Mathematik, Vol. 197, No. 2, 02.2022, p. 257-284.

Research output: Contribution to journalArticleResearchpeer review

Bauer W, Kumar VBK, Rajan R. Korovkin-type theorems on B(H) and their applications to function spaces. Monatshefte für Mathematik. 2022 Feb;197(2):257-284. Epub 2021 Apr 26. doi: 10.1007/s00605-021-01549-1
Bauer, Wolfram ; Kumar, V. B. Kiran ; Rajan, Rahul. / Korovkin-type theorems on B(H) and their applications to function spaces. In: Monatshefte für Mathematik. 2022 ; Vol. 197, No. 2. pp. 257-284.
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