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Generalized weak demicompactness involving measure of non-strict-singularity

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Abstract

This paper is devoted to a characterization of the notion of generalized weakly demicompact linear operators acting on a Banach space introduced in [8]. Our results are formulated in terms of measures of non-strict-singularity and strictly singular operators. Theses results are used to discuss the incidence of some perturbation results on the behavior of the closure of unbounded \(2\times 2\) block operator matrices.

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Authors and Affiliations

  1. Department of Mathematics, Faculty of Sciences of Sfax, University of Sfax, Road Soukra Km 3.5, B.P. 1171, 3000, Sfax, Tunisia

    Imen Ferjani, Aref Jeribi & Bilel Krichen

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  1. Imen Ferjani
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  2. Aref Jeribi
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  3. Bilel Krichen
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Correspondence to Bilel Krichen.

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Communicated by Kalyan Sinha, Ph. D.

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Ferjani, I., Jeribi, A. & Krichen, B. Generalized weak demicompactness involving measure of non-strict-singularity. Indian J Pure Appl Math 52, 529–541 (2021). https://doi.org/10.1007/s13226-021-00055-2

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