Results 31 to 40 of about 85 (82)
On Berezin norm and Berezin number inequalities for sum of operators
Demonstratio MathematicaThe aim of this study is to obtain several inequalities involving the Berezin number and the Berezin norm for various combinations of operators acting on a reproducing kernel Hilbert space.
Altwaijry Najla +2 more
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Preservers of unitary similarity functions on Lie products of matrices
, 2020 In memory of Professor Hans Schneider MSC: 15A60 46B04 Keywords: Lie product Unitary similarity invariant function Pseudo spectrum Denote by M n the set of n ×n complex matrices. Let f : M n → [0, ∞) be a continuous map such that f (μU AU * ) = f (A) for
Chi-Kwong Li +2 more
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Some new forms and properties of Legendre matrix polynomials with two variables
Demonstratio MathematicaThis paper aims to introduce new significant forms of the Legendre matrix polynomials (LMPs) with two variables, and establish matrix differential recurrence relations and matrix partial differential recurrence relations for LMPs with two variables, and ...
Khammash Ghazi S. +3 more
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Crouzeix's conjecture, compressions of shifts, and classes of nilpotent matrices
Concrete OperatorsThis article studies the level set Crouzeix (LSC) conjecture, which is a weak version of Crouzeix’s conjecture that applies to finite compressions of the shift.
Bickel Kelly +4 more
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On the spectral norm of a doubly stochastic matrix and level-k circulant matrix
Special MatricesA simple proof using Birkhoff theorem is given for the result that the spectral norm of a doubly stochastic matrix is 1. We also show that the result generalizes the results of İpek, Bozkurt, and Jiang and Zhou on circulant matrices and rr-circulant ...
Jiang Zhao-Lin, Tam Tin-Yau
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Isometries Between Matrix Algebras
, 2007 As an attempt to understand linear isometries between C # -algebras without the surjectivity assumption, we study linear isometries between matrix algebras. Denote by Mm the algebra of mm complex matrices. If k n and # : M n k has the form
Chi-kwong Li +3 more
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Enhanced Young-type inequalities utilizing Kantorovich approach for semidefinite matrices
Open MathematicsThis article introduces new Young-type inequalities, leveraging the Kantorovich constant, by refining the original inequality. In addition, we present a range of norm-based inequalities applicable to positive semidefinite matrices, such as the Hilbert ...
Bani-Ahmad Feras +1 more
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Interpolation $H^{\infty}$ et théorèmes de plongements pour des fonctions rationnelles
, 2019 International audienceWe consider a Nevanlinna-Pick interpolation problem on finite sequences of the unit disc D constrained by Hardy and radial-weighted Bergman norms. We find sharp asymptotics on the corresponding interpolation constants.
Baranov, Anton, Zarouf, Rachid
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HIGHER-RANK NUMERICAL RANGES AND DILATIONS
, 2008 . For any n-by-n complex matrix A and any k, 1 ≤ k ≤ n, let Λ k(A) = {λ ∈ C: X ∗ AX = λI k for some n-by-k X satisfying X ∗ X = I k} be its rank-k numerical range.
Hwa-long Gau, Chi-kwong Li, Pei Yuan Wu
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If A Matrix Has Only A Single Eigenvalue How Sensitive Is This Eigenvalue?
, 1997 . For matrices with a single eigenvalue we analyse the sensitivity of the eigenvalue to perturbations in the matrix. We derive a closed form result that is similar in spirit to an analytical result by Lidskii; improve a bound by Henrici; and express the ...
Grace E. Cho, Ilse C.F. Ipsen
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