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In this paper, we aim to introduce and characterize the concept of numerical radius orthogonality of operators on a complex Hilbert space $\mathcal{H}$ which are bounded with respect to the semi-norm induced by a positive operator $A$ on…

Functional Analysis · Mathematics 2024-08-13 Pintu Bhunia , Kais Feki , Kallol Paul

This article has two interpenetrating motifs. One is an exposition of some major ideas and techniques behind the use of block matrices, and especially their positivity properties. This is done by focussing on one major problem:…

Functional Analysis · Mathematics 2023-08-01 Rajendra Bhatia , Tanvi Jain

This paper establishes new upper bounds for the $A$-numerical radius of operator matrices in semi-Hilbertian spaces by leveraging the $A$-Buzano inequality and developing refined techniques for operator matrices. We present several sharp…

Functional Analysis · Mathematics 2025-07-08 M. H. M. Rashid

We develope new lower bounds for the $A$-numerical radius of semi-Hilbertian space operators, and applying these bounds we obtain upper bounds for the $A$-numerical radius of the commutators of operators. The bounds obtained here improve on…

Functional Analysis · Mathematics 2024-08-14 Pintu Bhunia , Kallol Paul

We present some upper and lower bounds for the numerical radius of a bounded linear operator defined on complex Hilbert space, which improves on the existing upper and lower bounds. We also present an upper bound for the spectral radius of…

Functional Analysis · Mathematics 2024-08-13 Pintu Bhunia , Santanu Bag , Kallol Paul

In this paper we obtain some operator versions of Levin-Steckin integral inequality.

Functional Analysis · Mathematics 2020-05-12 Silvestru Sever Dragomir

We present a subgradient method for minimizing non-smooth, non-Lipschitz convex optimization problems. The only structure assumed is that a strictly feasible point is known. We extend the work of Renegar [5] by taking a different…

Optimization and Control · Mathematics 2018-02-28 Benjamin Grimmer

We propose a general alternating minimization algorithm for nonconvex optimization problems with separable structure and nonconvex coupling between blocks of variables. To fix our ideas, we apply the methodology to the problem of blind…

Optimization and Control · Mathematics 2018-02-07 Robert Hesse , D. Russell Luke , Shoham Sabach , Matthew K. Tam

In this article, we proved upper bounds for numerical radius of bounded linear operator and product of operators which generalize and improve existing inequalities. We also obtain a numerical radius inequality of invertible operator using…

Functional Analysis · Mathematics 2023-04-03 Raj Kumar Nayak

In this paper, we design a new iterative algorithm for solving pseudomonotone equilibrium problems in real Hilbert spaces. The advantage of our algorithm is that it requires only one strongly convex programming problem at each iteration.…

Optimization and Control · Mathematics 2018-04-06 Nguyen The Vinh

Let $A$ be a positive bounded linear operator acting on a complex Hilbert space $\big(\mathcal{H}, \langle \cdot\mid \cdot\rangle \big)$. Let $\omega_A(T)$ and ${\|T\|}_A$ denote the $A$-numerical radius and the $A$-operator seminorm of an…

Functional Analysis · Mathematics 2020-04-20 Kais Feki

The main target of this paper is to discuss operator Hermite--Hadamard inequality for convex functions, without appealing to operator convexity. Several forms of this inequality will be presented and some applications including norm and…

Functional Analysis · Mathematics 2019-08-07 Hamid Reza Moradi , Mohammad Sababheh , Shigeru Furuichi

In this paper, we begin by showing a new generalization of the celebrated Cauchy-Schwarz inequality for the inner product. Then, this generalization is used to present some bounds for the Euclidean operator radius and the Euclidean operator…

Functional Analysis · Mathematics 2023-10-09 Mohammad Sababheh , Hamid Reza Moradi

In this paper, we show several bounds for the numerical radius of a Hilbert space operator in terms of the Euclidean operator norm. The obtained forms will enable us to find interesting refinements of celebrated results in the literature.…

Functional Analysis · Mathematics 2023-09-21 Mohammad Sababheh , Hamid Reza Moradi , Mohammad Alomari

This paper introduces and investigates the concept of the $q$-numerical range for tuples of bounded linear operators in Hilbert spaces. We establish various inequalities concerning the $q$-numerical radius associated with these operator…

Functional Analysis · Mathematics 2024-10-08 Kais Feki , Arnab Patra , Jyoti Rani , Zakaria Taki

In applications throughout science and engineering one is often faced with the challenge of solving an ill-posed inverse problem, where the number of available measurements is smaller than the dimension of the model to be estimated. However…

Optimization and Control · Mathematics 2012-10-30 Venkat Chandrasekaran , Benjamin Recht , Pablo A. Parrilo , Alan S. Willsky

We make an experimental comparison of methods for computing the numerical radius of an $n\times n$ complex matrix, based on two well-known characterizations, the first a nonconvex optimization problem in one real variable and the second a…

Numerical Analysis · Mathematics 2023-10-10 Tim Mitchell , Michael L. Overton

This work presents a parallel variant of the algorithm introduced in [Acceleration of block coordinate descent methods with identification strategies Comput. Optim. Appl. 72(3):609--640, 2019] to minimize the sum of a partially separable…

Optimization and Control · Mathematics 2025-08-06 Ronaldo Lopes , Sandra A. Santos , Paulo J. S. Silva

In this paper we propose accelerated gradient descent schemes for convex optimization problems in Hilbert space. We consider inexact oracle case.

Optimization and Control · Mathematics 2019-10-16 Alexander Gasnikov , Sergey Kabanikhin , Ahmed Mohammed , Maxim Shishlenin

Mercer inequality for convex functions is a variant of Jensen's inequality, with an operator version that is still valid without operator convexity. This paper is two folded. First, we present a Mercer-type inequality for operators without…

Functional Analysis · Mathematics 2020-03-06 H. R. Moradi , S. Furuichi , M. Sababheh