Results 11 to 20 of about 53 (53)
Determinantal inequalities for J -accretive dissipative matrices [PDF]
, 2017 In this note we determine bounds for the determinant of the sum of two J -accretive dissipative matrices with prescribed spectra.
BEBIANO, Natália +1 more
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Numerical Range on Weighted Hardy Spaces as Semi Inner Product Spaces
Analele 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 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
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New Inequalities and an Integral Expression for the 𝒜‐Berezin Number
Journal of Mathematics, Volume 2026, Issue 1, 2026.This work examines a reproducing kernel Hilbert space XF,·,· constructed on a nonempty set F. Our investigation focuses on the A‐Berezin number and the A‐Berezin norm, where A denotes a positive bounded linear operator acting on XF. For an A‐bounded linear operator B, the A‐Berezin seminorm is defined by BberA=supλ,ν∈FBu∧λ,u∧νA, where u∧λ and u∧ν are ...
Salma Aljawi +4 more
wiley +1 more source
Hilbert–Schmidt‐Type Radii of Operator Pairs
Journal 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]
, 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
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Function theory, geometry, and circular numerical ranges
Concrete OperatorsWe introduce the reader to partial isometries and their properties. In particular, we consider the Gau-Wang-Wu conjecture from 2016: When is the numerical range of a partial isometry circular?
Adams Gregory, Gorkin Pamela
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Convexity around the Unit of a Banach Algebra [PDF]
, 2008 2000 Mathematics Subject Classification: Primary: 46B20. Secondary: 46H99, 47A12.We estimate the (midpoint) modulus of convexity at the unit 1 of a Banach algebra A showing that inf {max±||1 ± x|| − 1 : x ∈ A, ||x||=ε} ≥ (π/4e)ε²+o(ε²) as ε → 0. We also
Vishnyakova, Anna +3 more
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Domaine Numérique du produit AB avec A normal [PDF]
, 2006 2000 Mathematics Subject Classification: 18B30, 47A12.Let A, B be two linear operators on a complex Hilbert space H. We extend a Bouldin's result (1969) conserning W(AB) - the numerical range of the product AB. We show, when AB = BA and A is normal, than
Kaadoud, Mohamed Chraïbi
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EP Elements in Rings and in Semigroups with Involution and in C*-algebras [PDF]
, 2015 This work includes a survey of most of the results concerning EP elements in semigroups and rings with involution and in C*-algebras. 2010 Mathematics Subject Classification: Primary 46L05, 46J05, 46H05, 46H30, 47A05, 47A53, 47A60, 15A09, 15A33, 16A28 ...
Karanasios, Sotirios
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