Results 11 to 20 of about 99 (60)
Cauchy-Schwarz type inequalities and applications to numerical radius inequalities
, 2020 We present new improvements of certain Cauchy–Schwarz type inequalities. As applications of the results obtained, we provide refinements of some numerical radius inequalities for Hilbert space operators. It is shown, among other inequalities, that if A ∈
F. Kıttaneh, H. Moradi
semanticscholar +1 more source
New norm equalities and inequalities for certain operator matrices
, 2020 We prove new norm equalities and inequalities for general n×n tridiagonal and antitridiagonal operator matrices, including pinching type inequalities for weakly unitarily invariant norms.
Watheq Bani-Domi +2 more
semanticscholar +1 more source
Joint numerical ranges: recent advances and applications minicourse by V. Müller and Yu. Tomilov
Concrete Operators, 2020 We present a survey of some recent results concerning joint numerical ranges of n-tuples of Hilbert space operators, accompanied with several new observations and remarks.
Müller V., Tomilov Yu.
doaj +1 more source
Fixed points of holomorphic mappings for domains in Banach spaces
Abstract and Applied Analysis, Volume 2003, Issue 5, Page 261-274, 2003., 2003 We discuss the Earle‐Hamilton fixed‐point theorem and show how it can be applied when restrictions are known on the numerical range of a holomorphic function. In particular, we extend the Earle‐Hamilton theorem to holomorphic functions with numerical range having real part strictly less than 1.
Lawrence A. Harris
wiley +1 more source
Operator inequalities via geometric convexity
Mathematical Inequalities & Applications, 2019 The main goal of this paper is to present new generalizations of some known inequalities for the numerical radius and unitarily invariant norms of Hilbert space operators.
M. Sababheh, H. Moradi, S. Furuichi
semanticscholar +1 more source
Some new operator inequalities
, 2020 In this article, we present some new inequalities for positive linear mappings that can be viewed as super multiplicative inequalities. As applications, we deduce some numerical radius inequalities.
M. Sababheh +2 more
semanticscholar +1 more source
Berezin number inequalities for operators
Concrete 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
General numerical radius inequalities for matrices of operators
Open 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
Operators with minimal pseudospectra and connections to normality
, 2020 This paper mainly studies the class of bounded linear operators A with minimal pseudospectra σε (A) = σ(A)+Dε for some ε > 0 , where σ(A) denotes the spectrum of A , and Dε denotes the open disk of radius ε centered at the origin.
Samir Raouafi
semanticscholar +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
doaj +1 more source