On Numerical Radius Inequalities for Operator Matrices
Sign Up to like & getrecommendations! Published in 2019 at "Numerical Functional Analysis and Optimization"
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
Sign Up to like & getrecommendations! Published in 2020 at "Hacettepe Journal of Mathematics and Statistics"
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
Sign Up to like & getrecommendations! Published in 2019 at "Filomat"
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
Sign Up to like & getrecommendations! Published in 2020 at "Filomat"
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
Sign Up to like & getrecommendations! Published in 2020 at "Filomat"
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
Left and right Browder operator matrices on a Banach space
Sign Up to like & getrecommendations! Published in 2024 at "Filomat"
DOI: 10.2298/fil2407277l
Abstract: Let X,Y be Banach spaces, and upper triangular operator matrices acting on X?Y are studied. Given bounded operators A, B, we obtain several equivalent conditions forMX = [A X 0 B] to be a left… read more here.
Keywords: operator; right browder; browder operator; browder ... See more keywords
Numerical radius bounds for certain operator matrices
Sign Up to like & getrecommendations! Published in 2025 at "Filomat"
DOI: 10.2298/fil2513341a
Abstract: Due to the unavoidable role of operator matrices in advancing the study of the numerical radius, we further investigate upper and lower bounds for the numerical radii of certain operator matrices. The obtained results are… read more here.
Keywords: operator; numerical radius; radius bounds; operator matrices ... See more keywords
PROPERTIES OF OPERATOR MATRICES
Sign Up to like & getrecommendations! Published in 2020 at "Journal of The Korean Mathematical Society"
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
Sign Up to like & getrecommendations! Published in 2020 at "Tamkang Journal of Mathematics"
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
Sign Up to like & getrecommendations! Published in 2021 at "Journal of Mathematical Inequalities"
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