Results 251 to 260 of about 69,047 (280)

Linear operators preserving the numerical range (radius) on triangular matrices

Linear and Multilinear Algebra, 2001
We characterize those linear operators on triangular or diagonal matrices preserving the numerical range or radius.
Chi-Kwong Li, Peter Šemrl, Graca Soares
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Linear operators that preserve the c -numerical range or radius of matrices

Linear and Multilinear Algebra, 1988
Let For any n × n matrix A, define the c-numerical range and the c-numerical radius by and rc (A) = max{|z|: z∈ W c (A)} respectively. We give a characterization for those linear operators Twhich satisfy for all matrix A. Moreover, we give a full description for the extreme points of the unit ball in the real linear space of n × n hermitian matrices ...
Chi-Kwong Li, Nam-Kiu Tsing
openaire   +1 more source

Duality between some linear preservers problems: the invariance of thec-numerical range, thec-numerical radius and certain matrix sets

Linear and Multilinear Algebra, 1988
Let C be a hermitian matrix. We show that the C-numerical range or C-numerical radius preservers are actually the dual operators of some matrix set preservers. We use the known results about the C-numerical range preservers to determine the structure of their dual operators.
Chi-Kwong Li, Nam-Kiu Tsing
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Weighted numerical range and weighted numerical radius for even-order tensor via Einstein product

Rendiconti del Circolo Matematico di Palermo Series 2
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Aaisha Be, Debasisha Mishra
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The invarianee ofC-numerical rangeC-numericai radius, and their dual problems

Linear and Multilinear Algebra, 1991
Let C be an n×n normal matrix. Let For any n×n matrix A, define the C-numerical range and the C-numerical radius of A by and respectively. We give a characierizaiion for those linear operators T which satisfy one of the following properties: .
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Some improvements of numerical radius inequalities of operators and operator matrices

Linear and Multilinear Algebra, 2022
Pintu Bhunia, Kallol Paul
exaly  

Numerical Ranges and Numerical Radius of Truncated Toeplitz Operators in the Case u = zn

International Journal of Mathematics Trends and Technology, 2023
openaire   +1 more source

Some extended numerical radius inequalities

Linear and Multilinear Algebra, 2021
Satyajit Sahoo, Nirmal Chandra Rout, Mohammad Sababheh   +2 more
exaly  

Some estimates for the generalized numerical radius

Journal of Analysis, 2023
Mojtaba Bakherad, Rahmatollah Lashkaripour, Mohammad Sababheh   +2 more
exaly  

The weighted numerical radius

Annals of Functional Analysis, 2021
Alemeh Sheikhhosseini, Maryam Khosravi, Mohammad Sababheh   +2 more
exaly