scholarly journals On relative essential spectra of a 3 x 3 operator matrix involving relative generalized weak demicompactness

Filomat ◽  
2020 ◽  
Vol 34 (13) ◽  
pp. 4271-4286
Author(s):  
Imen Ferjani ◽  
Aref Jeribi ◽  
Bilel Krichen
Keyword(s):  
Block Matrix ◽  
Matrix Operator ◽  
Operator Matrix ◽  
Essential Spectra

In this paper, we investigate the relative essential spectra of a 3 x 3 block matrix operator with unbounded entries and with domain consisting of vectors satisfying certain relations between their components. Our results are formulated in term of relative generalized weak demicompactness and measure of non-strict-singularity.

scholarly journals Some advances on essential spectra of one sided operator matrix with application

2021 ◽  
Author(s):  
Marwa Belghith ◽  
Nedra Moalla ◽  
Ines Walha
Keyword(s):  
Differential Equations ◽  
Unbounded Operator ◽  
Matrix Form ◽  
Operator Matrix ◽  
Essential Spectra ◽  
The One

This paper deals with a new description of the one sided operator matrix form, as a generalization of the case of the unbounded operator matrix with the non diagonal domain, to investigate some advances in the analysis of some essential spectra under weaker hypotheses then the one provided in the works of [17, 33]. An example of differential equations is tested to ensure the validity of the abstract results.

scholarly journals Perturbation theory, M-essential spectra of operator matrices

Filomat ◽  
2020 ◽  
Vol 34 (4) ◽  
pp. 1187-1196
Author(s):  
Boulbeba Abdelmoumen ◽  
Sonia Yengui
Keyword(s):  
Banach Space ◽  
Perturbation Theory ◽  
Banach Spaces ◽  
General Class ◽  
Operator Matrix ◽  
Operator Matrices ◽  
Essential Spectra ◽  
Block Operator Matrix ◽  
Block Operator ◽  
Block Operator Matrices

In this paper, we will establish some results on perturbation theory of block operator matrices acting on Xn, where X is a Banach space. These results are exploited to investigate the M-essential spectra of a general class of operators defined by a 3x3 block operator matrix acting on a product of Banach spaces X3.

Essential Spectra, Matrix Operator and Applications

2009 ◽  
Vol 111 (3) ◽  
pp. 319-337 ◽  
Author(s):  
Salma Charfi ◽  
Aref Jeribi ◽  
Ines Walha
Keyword(s):  
Matrix Operator ◽  
Essential Spectra

Some classes of ideal convergent sequences and generalized difference matrix operator

Filomat ◽  
2017 ◽  
Vol 31 (6) ◽  
pp. 1827-1834 ◽  
Author(s):  
S.A. Mohiuddine ◽  
B. Hazarika
Keyword(s):  
Matrix Operator ◽  
Difference Matrix ◽  
Convergent Sequences

Solvability of a 2 x 2 block operator matrix of chandrasekhar type on a Bananch algebra

Filomat ◽  
2017 ◽  
Vol 31 (16) ◽  
pp. 5169-5175 ◽  
Author(s):  
H.H.G. Hashem
Keyword(s):  
Fixed Point ◽  
Fixed Point Theorem ◽  
Existence Of Solutions ◽  
Banach Algebras ◽  
Operator Matrix ◽  
Nonlinear Operators ◽  
Block Operator Matrix ◽  
Block Operator ◽  
Quadratic Integral ◽  
Quadratic Integral Equations

In this paper, we study the existence of solutions for a system of quadratic integral equations of Chandrasekhar type by applying fixed point theorem of a 2 x 2 block operator matrix defined on a nonempty bounded closed convex subsets of Banach algebras where the entries are nonlinear operators.

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