H. Najafi

activity

20112024

most citedOperator maps of Jensen-type

9 citations · 11 across the 8 of their papers we have counts for

collaborators

8 papers

math.FA2024

Operator mean inequalities and Kwong functions

Nahid Gharakhanlu, Mohammad Sal Moslehian, Hamed Najafi

In this paper, we study operator mean inequalities for the weighted arithmetic, geometric and harmonic means. We give a slight modification of Audenaert's result to show the relati…

math.CO2022

Characterization of some classes of graphs and their products as frame graph

H. Najafi, F. Abdollahi

To each finite frame $φ$ in an inner product space $H$ we associate a simple graph $G (φ)$ , called {\it frame graph}, with the vectors of the frame as vertices and there i…

math.FA2017★ 9 cited

Operator maps of Jensen-type

Frank Hansen, Mohammad Sal Moslehian, Hamed Najafi

Let $B_{J} (H)$ denote the set of self-adjoint operators acting on a Hilbert space $H$ with spectra contained in an open interval $J$ . A map $Φ\colon\mathb…

math.FA2016

Estimates of operator convex and operator monotone functions on bounded intervals

M. Fujii, M. S. Moslehian, H. Najafi +1

Recently the behavior of operator monotone functions on unbounded intervals with respect to the relation of strictly positivity has been investigated. In this paper we deeply study…

math.OA2013

Deformation of involution and multiplication in a C*-algebra

H. Najafi, M. S. Moslehian

We investigate the deformation of involution and multiplication in a unital $C^{*}$ -algebra when its norm is fixed. Our main result is to present all multiplications and involutions…

math.FA2012★ 2 cited

An extension of the Lowner-Heinz inequality

Mohammad Sal Moslehian, Hamed Najafi

We extend the celebrated Löwner--Heinz inequality by showing that if $A, B$ are Hilbert space operators such that $A > B \geq 0$ , then A^r - B^r \geq ||A||^r-(||A||- \frac{1}{||(A-…

math.OA2012

On the binary relation $\leq_{u}$ on self-adjoint Hilbert space operators

M. S. Moslehian, S. M. S. Nabavi Sales, H. Najafi

Given self-adjoint operators $A, B \in B (H)$ it is said $A \leq_{u} B$ whenever $A \leq U^{*} B U$ for some unitary operator $U$ . We show that $A \leq_{u} B$ if and only if $f…

math.FA2011

Around Operator Monotone Functions

M. S. Moslehian, H. Najafi

We show that the symmetrized product $A B + B A$ of two positive operators $A$ and $B$ is positive if and only if $f (A + B) \leq f (A) + f (B)$ for all non-negative operator monotone function…