scholarly journals Some mappings related to Levinson’s inequality for Hilbert space operators

Filomat ◽  
2017 ◽  
Vol 31 (7) ◽  
pp. 1995-2009 ◽  
Author(s):  
Jadranka Micic ◽  
Josip Pecaric

We observe properties of some mappings related to the Davis-Choi-Jensen inequality for Hilbert space operators. Using these results, we observe properties of some mappings related to Levinson?s operator inequality. Consequently, we obtain several refinements for each of these inequalities.

2018 ◽  
Vol 25 (1) ◽  
pp. 93-107
Author(s):  
Jamal Rooin ◽  
Akram Alikhani ◽  
Mohammad Sal Moslehian

AbstractThe aim of this paper is to present a comprehensive study of operatorm-convex functions. Let{m\in[0,1]}, and{J=[0,b]}for some{b\in\mathbb{R}}or{J=[0,\infty)}. A continuous function{\varphi\colon J\to\mathbb{R}}is called operatorm-convex if for any{t\in[0,1]}and any self-adjoint operators{A,B\in\mathbb{B}({\mathscr{H}})}, whose spectra are contained inJ, we have{\varphi(tA+m(1-t)B)\leq t\varphi(A)+m(1-t)\varphi(B)}. We first generalize the celebrated Jensen inequality for continuousm-convex functions and Hilbert space operators and then use suitable weight functions to give some weighted refinements. Introducing the notion of operatorm-convexity, we extend the Choi–Davis–Jensen inequality for operatorm-convex functions. We also present an operator version of the Jensen–Mercer inequality form-convex functions and generalize this inequality for operatorm-convex functions involving continuous fields of operators and unital fields of positive linear mappings. Employing the Jensen–Mercer operator inequality for operatorm-convex functions, we construct them-Jensen operator functional and obtain an upper bound for it.


2021 ◽  
Vol 45 (02) ◽  
pp. 191-202
Author(s):  
Z. HEYDARBEYGI ◽  
M. AMYARI

In this paper, we get an improvement of the Hölder-McCarthy operator inequality in the case when r ≥ 1 and refine generalized inequalities involving powers of the numerical radius for sums and products of Hilbert space operators.


2015 ◽  
pp. 1271-1285
Author(s):  
Jadranka Mić ć Hot ◽  
Josip Pečarić ◽  
Marjan Praljak

Author(s):  
Mohammad Alomari

In this work, some operator trace inequalities are proved. An extension of Klein's inequality for all Hermitian matrices is proved. A non-commutative version (or Hansen-Pedersen version) of the Jensen trace inequality is provided as well. A generalization of the result for any positive Hilbert space operators acts on a positive unital linear map is established.


2003 ◽  
Vol 4 (2) ◽  
pp. 301
Author(s):  
A. Bourhim

<p>In this talk, to be given at a conference at Seconda Università degli Studi di Napoli in September 2001, we shall describe the set of analytic bounded point evaluations for an arbitrary cyclic bounded linear operator T on a Hilbert space H and shall answer some questions due to L. R. Williams.</p>


2012 ◽  
Vol 436 (5) ◽  
pp. 1516-1527 ◽  
Author(s):  
Omar Hirzallah ◽  
Fuad Kittaneh ◽  
Mario Krnić ◽  
Neda Lovričević ◽  
Josip Pečarić

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