Please use this identifier to cite or link to this item:
http://hdl.handle.net/10662/8344
Title: | Spectral properties for polynomial and matrix operators involving demicompactness classes |
Authors: | Ben Brahim, Fatma Jeribi, Aref Krichen, Bilel |
Keywords: | Operador matricial;Operadores lineales;Operadores Fredholm y semi-Fredholm;Teoría de la perturbación;Espectros esenciales;Matrix operator;Demicompact linear operator;Fredholm and semi-Fredholm operators;Perturbation theory;Essential spectra |
Issue Date: | 2018 |
Publisher: | Universidad de Extremadura |
Abstract: | The first aim of this paper is to show that a polynomially demicompact operator satisfying certain conditions is demicompact. Furthermore, we give a refinement of the Schmoëger and the Rakocević essential spectra of a closed linear operator involving the class of demicompact ones. The second aim of this work is devoted to provide some sufficient conditions on the inputs of a closable block operator matrix to ensure the demicompactness of its closure. An example involving the Caputo derivative of fractional of order α is provided. Moreover, a study of the essential spectra and an investigation of some perturbation results. |
URI: | http://hdl.handle.net/10662/8344 |
DOI: | 10.17398/2605-5686.33.1.11 |
Appears in Collections: | Extracta Mathematicae Vol. 33, nº 1 (2018) |
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2605-5686_33_1_11.pdf | 147,43 kB | Adobe PDF | View/Open |
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