Results 11 to 20 of about 450 (52)

A Gr\"uss type operator inequality [PDF]

open access: yes, 2016
In [P. Renaud, "A matrix formulation of Gr\"uss inequality", Linear Algebra Appl. 335 (2001), 95--100] it was proved an operator inequality involving the usual trace functional.
Bottazzi, Tamara, Conde, Cristian
core   +2 more sources

Numerical radius inequalities of operator matrices with applications

open access: yes, 2020
We present upper and lower bounds for the numerical radius of $2 \times 2$ operator matrices which improves on the existing bound for the same.
Bag, Santanu   +2 more
core   +1 more source

Norm and Numerical Radius Inequalities for Sums of Bounded Linear Operators in Hilbert Spaces [PDF]

open access: yes, 2006
Some inequalities for the operator norm and numerical radius of sums of bounded linear operators in Hilbert spaces are given.
Dragomir, Sever S
core   +2 more sources

General numerical radius inequalities for matrices of operators

open access: yesOpen Mathematics, 2016
Let Ai ∈ B(H), (i = 1, 2, ..., n), and T=[0⋯0A1⋮⋰A200⋰⋰⋮An0⋯0] $ T = \left[ {\matrix{ 0 & \cdots & 0 & {A_1 } \cr \vdots & {\mathinner{\mkern2mu\raise1pt\hbox{.}\mkern2mu \raise4pt\hbox{.}\mkern2mu\raise7pt\hbox{.}\mkern1mu}} & {A_2 } & 0
Al-Dolat Mohammed   +3 more
doaj   +1 more source

Lipschitz slices and the Daugavet equation for Lipschitz operators [PDF]

open access: yes, 2014
We introduce a substitute for the concept of slice for the case of non-linear Lipschitz functionals and transfer to the non-linear case some results about the Daugavet and the alternative Daugavet equations previously known only for linear ...
Kadets, Vladimir   +3 more
core   +1 more source

Numerical Range on Weighted Hardy Spaces as Semi Inner Product Spaces

open access: yesAnalele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2017
The semi-inner product, in the sense of Lumer, on weighted Hardy space which generate the norm is unique. Also we will discuss some properties of the numerical range of bounded linear operators on weighted Hardy spaces.
Heydari Mohammad Taghi
doaj   +1 more source

A class of tridiagonal operators associated to some subshifts

open access: yesOpen Mathematics, 2016
We consider a class of tridiagonal operators induced by not necessary pseudoergodic biinfinite sequences. Using only elementary techniques we prove that the numerical range of such operators is contained in the convex hull of the union of the numerical ...
Hernández-Becerra Christian   +1 more
doaj   +1 more source

Remarks on the Crouzeix-Palencia proof that the numerical range is a $(1+\sqrt2)$-spectral set

open access: yes, 2018
Crouzeix and Palencia recently showed that the numerical range of a Hilbert-space operator is a $(1+\sqrt2)$-spectral set for the operator. One of the principal ingredients of their proof can be formulated as an abstract functional-analysis lemma.
Ransford, Thomas, Schwenninger, Felix
core   +1 more source

Hilbert–Schmidt‐Type Radii of Operator Pairs

open access: yesJournal of Function Spaces, Volume 2025, Issue 1, 2025.
Let C2H be the Hilbert–Schmidt class on a complex separable Hilbert space H. In light of the recent definition of the weighted numerical radius and motivated by the definition of the Hilbert–Schmidt numerical radius of a pair of operators, we introduce the definition of the weighted Hilbert–Schmidt numerical radius of a pair of operators.
Bashar Mayyas   +2 more
wiley   +1 more source

Generalized Derivations and Norm Equality in Normed Ideals [PDF]

open access: yes, 2011
2000 Mathematics Subject Classification: 47A10, 47A12, 47A30, 47B10, 47B20, 47B37, 47B47, 47D50.We compare the norm of a generalized derivation on a Hilbert space with the norm of its restrictions to Schatten norm ...
Barraa, Mohamed
core  

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