Results 31 to 40 of about 654 (59)

Some inequalities for unitarily invariant norms of matrices

open access: yesJournal of Inequalities and Applications, 2011
This article aims to discuss inequalities involving unitarily invariant norms. We obtain a refinement of the inequality shown by Zhan. Meanwhile, we give an improvement of the inequality presented by Bhatia and Kittaneh for the Hilbert-Schmidt norm ...
Wang Shaoheng, Zou Limin, Jiang Youyi
doaj  

Numerical radius inequalities and its applications in estimation of zeros of polynomials

open access: yes, 2019
We present some upper and lower bounds for the numerical radius of a bounded linear operator defined on complex Hilbert space, which improves on the existing upper and lower bounds. We also present an upper bound for the spectral radius of sum of product
Abu-Omar   +19 more
core   +1 more source

The perturbation of Drazin inverse and dual Drazin inverse

open access: yesSpecial Matrices
In this study, we derive the Drazin inverse (A+εB)D{\left(A+\varepsilon B)}^{D} of the complex matrix A+εBA+\varepsilon B with Ind(A+εB)>1{\rm{Ind}}\left(A+\varepsilon B)\gt 1 and Ind(A)=k{\rm{Ind}}\left(A)=k and the group inverse (A+εB)#{\left(A ...
Wang Hongxing, Cui Chong, Wei Yimin
doaj   +1 more source

Concrete minimal 3 × 3 Hermitian matrices and some general cases

open access: yesDemonstratio Mathematica, 2017
Given a Hermitian matrix M ∈ M3(ℂ) we describe explicitly the real diagonal matrices DM such that ║M + DM║ ≤ ║M + D║ for all real diagonal matrices D ∈ M3(ℂ), where ║ · ║ denotes the operator norm.
Klobouk Abel H., Varela Alejandro
doaj   +1 more source

Private quantum codes: introduction and connection with higher rank numerical ranges

open access: yes, 2013
We give a brief introduction to private quantum codes, a basic notion in quantum cryptography and key distribution. Private code states are characterized by indistinguishability of their output states under the action of a quantum channel, and we show ...
Kribs, D. W., Plosker, S.
core   +1 more source

Explicit inverse of symmetric, tridiagonal near Toeplitz matrices with strictly diagonally dominant Toeplitz part

open access: yesSpecial Matrices
Let Tn=tridiag(−1,b,−1){T}_{n}={\rm{tridiag}}\left(-1,b,-1), an n×nn\times n symmetric, strictly diagonally dominant tridiagonal matrix (∣b∣>2| b| \gt 2). This article investigates tridiagonal near-Toeplitz matrices T˜n≔[t˜i,j]{\widetilde{T}}_{n}:= \left[
Kurmanbek Bakytzhan   +2 more
doaj   +1 more source

Berezin number inequalities for operators

open access: yesConcrete Operators, 2019
The Berezin transform à of an operator A, acting on the reproducing kernel Hilbert space ℋ = ℋ (Ω) over some (non-empty) set Ω, is defined by Ã(λ) = 〉Aǩ λ, ǩ λ〈 (λ ∈ Ω), where k⌢λ=kλ‖kλ‖${\mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown ...
Bakherad Mojtaba, Garayev Mubariz T.
doaj   +1 more source

On Berezin norm and Berezin number inequalities for sum of operators

open access: yesDemonstratio Mathematica
The 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
doaj   +1 more source

On the spectral norm of a doubly stochastic matrix and level-k circulant matrix

open access: yesSpecial Matrices
A 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
doaj   +1 more source

Symmetric norms and reverse inequalities to Davis and Hansen-Pedersen characterizations of operator convexity

open access: yes, 2005
Some rearrangement inequalities for symmetric norms on matrices are given as well as related results for operator convex functions.Comment: to appear in ...
Bourin, Jean-Christophe
core   +1 more source

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