94 citations · 127 across the 16 of their papers we have counts for
24 papers
Integral Representations and Sharp Numerical Radius Inequalities for Hilbert Space Operators
Wasim Audeh, Fuad Kittaneh, Hamid Reza Moradi
We study the numerical radius \(ω(T)\) of a bounded linear operator \(T\) on a complex Hilbert space. Write \(T=A+iB\), where \(A\) and \(B\) are the real and imaginary parts of \(…
On the Commutant of Invertible Positive Operators
Fuad Kittaneh, Carlos S. Kubrusly, Mohammad Sal Moslehian
An important result due to Radjabalipour asserts that if ${A\in\BB(\H)}$ is an invertible positive operator and ${T\in\BB(\H)}$ is arbitrary, then the operator sequence $\{A^{-n}TA…
On the Orlicz function estimations of the -Davis--Wielandt radius in -algebra
Debarati Bhattacharya, Fuad Kittaneh, Arnab Patra
We present a systematic study of -Davis--Wielandt radius estimates for elements in a unital -algebra through an Orlicz function approach. We derive novel bounds for the alg…
A proof of the Fong--Tsui conjecture
Mohamed Amine Aouichaoui, Fuad Kittaneh, Yicen Ma
We prove that a bounded operator on a complex Hilbert space is self-adjoint whenever $|T|\leq|\re T|$, as conjectured by Fong and Tsui \cite{FT}.
Finite-Corner Reconstruction and Separation for Cones of Normal Maps
Mohsen Kian, Fuad Kittaneh
We develop a finite-corner framework for convex cones of normal maps between \(\mathcal B(\mathcal H)\) and \(\mathcal B(\mathcal K)\). The basic structural assumption is stability…
Improved upper bounds for the Berezin numbers of operators on reproducing kernel Hilbert spaces
Riddhick Birbonshi, Sumon Ghosh, Fuad Kittaneh +2
In this article, several upper bounds for the Berezin numbers of bounded linear operators on reproducing kernel Hilbert spaces are obtained through the use of interpolation paths o…
On the geometry of the algebraic Davis--Wielandt shell and norm-parallelism in -algebra
Debarati Bhattacharya, Fuad Kittaneh, Arnab Patra +1
This article is devoted to the study of the Davis--Wielandt shell and the Davis--Wielandt radii of elements in a -algebra. Utilizing a state-space approach, several geometric…
Some spectral properties and convergence of the -numerical radius and -Crawford number
Pembe Ipek Al, Zameddin I. Ismailov, Fuad Kittaneh +1
In this study, some estimates are given for the -numerical radius and -Crawford number via the -numerical radius and -Crawford number for the -bounded…
On the estimation of the -numerical radius via Orlicz functions
Fuad Kittaneh, Arnab Patra, Jyoti Rani
This study utilizes Orlicz functions to provide refined lower and upper bounds on the q-numerical radius of an operator acting on a Hilbert space. Additionally, the concept of q-se…
On inequalities involving the spherical operator transforms
Fuad Kittaneh, Satyajit Sahoo, Hranislav Stanković
This paper explores refinements of some operator norm inequalities through the generalized spherical Aluthge transform and the spherical Heinz transform. We introduce the spherical…
An extension of the -operator radii
Fuad Kittaneh, Ali Zamani
We define a function on the -algebra of all bounded linear Hilbert space operators, which generalizes the operator radii, and we present some basic properties of this fun…
Characterizations of -Birkhoff--James orthogonality and -parallelism
Fuad Kittaneh, Ali Zamani
We study the concepts of Birkhoff--James orthogonality and parallelism in Hilbert space operators, induced by the operator radius norm . In particular, we completely ch…
New -numerical radius equalities and inequalities for certain operator matrices and applications
Soumitra Daptari, Fuad Kittaneh, Satyajit Sahoo
The main goal of this article is to establish several new -numerical radius equalities and inequalities for cross-diagonal, left circulant, skew left circul…
Norm and numerical radius inequalities for operator matrices
Fuad Kittaneh, Hamid Reza Moradi, Mohammad Sababheh
Operator matrices have played a significant role in studying Hilbert space operators. In this paper, we discuss further properties of operator matrices and present new estimates fo…
Numerical radii of accretive matrices
Yassine Bedrani, Fuad Kittaneh, Mohammed Sababheh
The numerical radius of a matrix is a scalar quantity that has many applications in the study of matrix analysis. Due to the difficulty in computing the numerical radius, inequalit…
On the weighted Geometric mean of accretive matrices
Yassine Bedrani, Fuad Kittaneh, Mohammed Sababheh
In this paper, we discuss new inequalities for accretive matrices through non standard domains. In particular, we present several relations for and , when a…
From positive to accretive matrices
Yassine Bedrani, Fuad Kittaneh, Mohammed Sababheh
The main goal of this paper is to discuss the recent advancements of operator means for accretive matrices in a more general setting. In particular, we present the general form gov…
Quadratic interpolation of the Heinz means
Fuad Kittaneh, Mohammad Sal Moslehian, Mohammad Sababheh
The main goal of this article is to present several quadratic refinements and reverses of the well known Heinz inequality, for numbers and matrices, where the refining term is a qu…
Numerical radius inequalities involving commutators of operators
Mojtaba Bakherad, Fuad Kittaneh
We prove numerical radius inequalities involving commutators of operators and certain analytic functions. Among other inequalities, it is shown that if and are boun…
Further generalizations, refinements, and reverses of the Young and Heinz inequalities
Yousef Al-Manasrah, Fuad Kittaneh
In this paper, we give a new inequality for convex functions of real variables, and we apply this inequality to obtain considerable generalizations, refinements, and reverses of th…
Unitarily invariant norm inequalities for elementary operators involving operators
Fuad Kittaneh, Mohammad Sal Moslehian, Mohammad Sababheh
In this paper, motivated by perturbation theory of operators, we present some upper bounds for in terms of and in te…
Cartesian decomposition and Numerical radius inequalities
Fuad Kittaneh, Mohammad Sal Moslehian, Takeaki Yamazaki
We show that if is the Cartesian decomposition of , then for , . We then apply…
Problems and Conjectures in Matrix and Operator Inequalities
K. M. R. Audenaert, F. Kittaneh
We present a treasure trove of open problems in matrix and operator inequalities, of a functional analytic nature, and with various degrees of hardness.
Schatten p-norm inequalities related to a characterization of inner product spaces
O. Hirzallah, F. Kittaneh, M. S. Moslehian
Let be operators acting on a separable complex Hilbert space such that . It is shown that if belong to a Schatten -class, for s…