On Numerical Radius Inequalities for Operator Matrices
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DOI: 10.1080/01630563.2018.1549073
Abstract: Abstract The aim of this article is to prove several new numerical radius inequalities for n × n operator matrices on a Hilbert space. Let be complex Hilbert spaces, and let be an n × n operator matrix with… read more here.
Keywords: radius; radius inequalities; operator matrices; numerical radius ... See more keywords
S-spectra and S-essential pseudospectra of the diagonal block operator matrices
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DOI: 10.15672/hujms.701108
Abstract: In this article, the relationships between the $S$-spectra, the $ S$-spectral radius, the $ \epsilon$-$S$-essential pseudospectra, and the $ \epsilon$-$S$-essential pseudospectral radius of the diagonal block operator matrices in the direct sum of Banach spaces… read more here.
Keywords: operator matrices; diagonal block; essential pseudospectra; block operator ... See more keywords
Approximation of the block numerical range of block operator matrices
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DOI: 10.2298/fil1912877y
Abstract: In this paper we obtain an approximation of the block numerical range of bounded and unbounded block operator matrices by projection methods. read more here.
Keywords: block numerical; block; operator matrices; block operator ... See more keywords
On upper triangular operator 2 x 2 matrices over C*-algebras
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DOI: 10.2298/fil2003691i
Abstract: We study adjointable, bounded operators on the direct sum of two copies of the standard Hilbert C*-module over a unital C*-algebra A that are given by upper triangular 2 by 2 operator matrices. Using the… read more here.
Keywords: triangular operator; upper triangular; matrices algebras; operator matrices ... See more keywords
Operator matrices and their Weyl type theorems
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DOI: 10.2298/fil2010191a
Abstract: We denote the collection of the 2× 2 operator matrices with (1, 2)-entries having closed range by S. In this paper, we study the relations between the operator matrices in the class S and their… read more here.
Keywords: operator matrices; operator; matrices weyl; type theorems ... See more keywords
PROPERTIES OF OPERATOR MATRICES
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DOI: 10.4134/jkms.j190439
Abstract: Let S be the collection of the operator matrices ( A C Z B ) where the range of C is closed. In this paper, we study the properties of operator matrices in the class… read more here.
Keywords: properties operator; matrices class; operator matrices;
Property $(w)$ of upper triangular operator Matrices
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DOI: 10.5556/j.tkjm.51.2020.2256
Abstract: Let $M_C=\begin{pmatrix} A & C \\ 0 & B \\ \end{pmatrix}\in\LB(\x,\y)$ be be an upper triangulate Banach spaceoperator. The relationship between the spectra of $M_C$ and $M_0,$ and theirvarious distinguished parts, has been studied by… read more here.
Keywords: operator matrices; property; property upper; upper triangular ... See more keywords
A Chain of numerical radius inequalities in complex Hilbert space
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DOI: 10.7153/jmi-2021-15-77
Abstract: In this paper, we implement the improvement of numerical radius inequalities that were produced by Alomari MW. [Refinements of some numerical radius inequalities for Hilbert space operators. Linear and Multilinear Algebra. 2019 Jun 4:1-6] and… read more here.
Keywords: radius; radius inequalities; hilbert space; operator matrices ... See more keywords