Results 61 to 70 of about 414,757 (180)

New norm equalities and inequalities for operator matrices

Journal of Inequalities and Applications, 2016
We prove new inequalities for general 2 × 2 $2\times2$ operator matrices. These inequalities, which are based on classical convexity inequalities, generalize earlier inequalities for sums of operators. Some other related results are also presented. Also,
Feras Ali Bani-Ahmad, Watheq Bani-Domi
doaj   +1 more source

Unitarily invariant norms on operators

Acta Scientiarum Mathematicarum, 2022
Let $f$ be a symmetric norm on ${\mathbb R}^n$ and let ${\mathcal B}({\mathcal H})$ be the set of all bounded linear operators on a Hilbert space ${\mathcal H}$ of dimension at least $n$. Define a norm on ${\mathcal B}({\mathcal H})$ by $\|A\|_f = f(s_1(A), \dots, s_n(A))$, where $s_k(A) = \inf\{\|A-X\|: X\in {\mathcal B}({\mathcal H}) \hbox{ has rank ...
Chan, Jor-Ting, Li, Chi-Kwong
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Polynomials in operator space theory: matrix ordering and algebraic aspects

, 2017
We extend the $\lambda$-theory of operator spaces given by Defant and Wiesner (2014), that generalizes the notion of the projective, Haagerup and Schur tensor norm for operator spaces to matrix ordered spaces and Banach $*$-algebras. Given matrix regular
Kumar, Ajay, Luthra, Preeti, Rajpal, Vandana   +2 more
core   +1 more source

Operator norms on L(E)

Journal of Mathematical Analysis and Applications, 1983
For any Banach space E, all Banach algebra norms on L(E) are equivalent to the given operator norm on L(E). The authors characterize when a Banach algebra norm p on L(E) is an operator norm for some (equivalent) norm on E. In particular, p is an operator norm if and only if it is minimal with resepct to the pointwise ordering on norms; this generalizes
Jen-Chung Chuan, Kok-Keong Tan
openaire   +2 more sources

Norm estimates for operators in norm-attainable C*-algebras

European Journal of Mathematics and Applications, 2023
Norm estimates for various types of Banach algebra operators have been studied over decades with interesting results obtained. However, it still remains an open problem to determine the norm of an operator in a general Banach space setting. In this note,
Sabasi Omaoro, Benard Okelo, Omolo Ongati   +2 more
doaj  

Operator Norms of Powers of the Volterra Operator

Journal of Integral Equations and Applications, 1999
Let \(V: L^2[0,1]\to L^2[0, 1]\) be the Volterra operator defined by \(Vf(x)= \int^x_0 f(t) dt\). In the paper is proved that \(\lim_{m\to\infty} \|m!V^m\|={1\over 2}\). To obtain this, some more general results for the operator \(A: L^2[0,1]\to L^2[0,1]\) defined by \(Af(x)= \int^x_0 a(x- t) f(t) dt\), wehre \(a\) is a nonnegative, nondecreasing \(L^2\
openaire   +3 more sources

On the Norm of Certain Weighted Composition Operators on the Hardy Space

Abstract and Applied Analysis, 2009
We obtain a representation for the norm of certain compact weighted composition operator 𝐶𝜓,𝜑 on the Hardy space 𝐻2, whenever 𝜑(𝑧)=𝑎𝑧+𝑏 and 𝜓(𝑧)=𝑎𝑧−𝑏. We also estimate the norm and essential norm of a class of noncompact weighted composition operators ...
M. Haji Shaabani, B. Khani Robati
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Norm inequalities in operator ideals

Journal of Functional Analysis, 2008
23 ...
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Norm Estimates for Solutions of Polynomial Operator Equations

Journal of Mathematics, 2015
We consider the equations ∑k=0mcm-kAkXBk=C and ∑k=0mcm-kAkXBm-k=C, where ck∈C  (k=1,…,m), c0=1, A,B,C are given linear bounded operators in a Banach space and X is to be found. Representations of solutions are derived.
Michael Gil’
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On operator norms for hyperbolic groups [PDF]

Journal of Topology and Analysis, 2017
We estimate the operator norm of radial non-negative functions on hyperbolic groups. As a consequence, we show that several forms of Haagerup’s inequality are optimal.
openaire   +4 more sources