English
Related papers

Related papers: Operator inequalities I. Models and ergodicity

200 papers

In this article, we employ certain properties of the transform $C_{M,m}(A)=(MI-A^*)(A-mI)$ to obtain new inequalities for the bounded linear operator $A$ on a complex Hilbert space $\mathcal{H}$. In particular, we obtain new relations among…

Functional Analysis · Mathematics 2023-02-06 Mohammad Sababheh , Ibrahim Halil Gümüş , Hamid Reza Moradi

Iterates of quantum operations and their convergence are investigated in the context of mean ergodic theory. We discuss in detail the convergence of the iterates and show that the uniform ergodic theorem plays an essential role. Our results…

Mathematical Physics · Physics 2022-06-14 J. Z. Bernád

In this paper, more inequalities between the operator norm and its numerical radius, for the class of normal operators, are established. Some of the obtained results are based on recent reverse results for the Schwarz inequality in Hilbert…

Functional Analysis · Mathematics 2012-10-29 Sever Silvestru Dragomir

We generalize several inequalities involving powers of the numerical radius for product of two operators acting on a Hilbert space. For any $A, B, X\in \mathbb{B}(\mathscr{H})$ such that $A,B$ are positive, we establish some numerical…

Functional Analysis · Mathematics 2015-11-09 Mostafa Sattari , Mohammad Sal Moslehian , Takeaki Yamazaki

We establish new integral inequalities for the numerical radius and the operator norm of bounded linear operators on Hilbert spaces. Our results refine classical triangle-type and operator matrix inequalities by incorporating convex…

Functional Analysis · Mathematics 2026-02-17 Shiva Sheybani , Hamid Reza Moradi , Mohammad Sababheh

We study the Mercer inequality and its operator extension for superquadratic functions. In particular, we give a more general form of the Mercer inequality by replacing some constants by positive operators. As some consequences, our results…

Functional Analysis · Mathematics 2024-03-27 Mohsen Kian , Zainab Peymani Mazraj

In this paper, we present generalized P\'olya-Szeg\"o type inequalities for positive invertible operators on a Hilbert space for arbitrary operator means between the arithmetic and the harmonic means. As applications, we present Operator…

Functional Analysis · Mathematics 2020-01-07 Trung Hoa Dinh , Hamid Reza Moradi , Mohammad Sababheh

In this paper, we introduce the concept of operator arithmetic-geometrically convex functions for positive linear operators and prove some Hermite-Hadamard type inequalities for these functions. As applications, we obtain trace inequalities…

Functional Analysis · Mathematics 2016-03-16 Ali Taghavi , Vahid Darvish , Haji Mohammad Nazari

In this paper we introduce operator s-convex func- tions and establish some Hermite-Hadamard type inequalities in which some operator s-convex functions of positive operators in Hilbert spaces are involved.

Functional Analysis · Mathematics 2014-07-10 Amir Ghasem Ghazanfari

In this work, we consider the problem of learning nonlinear operators that correspond to discrete-time nonlinear dynamical systems with inputs. Given an initial state and a finite input trajectory, such operators yield a finite output…

Optimization and Control · Mathematics 2024-12-25 Mircea Lazar

This is a survey article on Mercer's Theorem in its most general form and its relations with the theory of reproducing kernel Hilbert spaces and the spectral theory of compact operators. We provide a modern introduction to the basics of the…

Functional Analysis · Mathematics 2025-12-09 Aurelian Gheondea

We study the typical behavior of bounded linear operators on infinite dimensional complex separable Hilbert spaces in the norm, strong-star, strong, weak polynomial and weak topologies. In particular, we investigate typical spectral…

Functional Analysis · Mathematics 2014-05-01 Tanja Eisner , Tamas Matrai

Motivated by the recent developments of pseudo-Hermitian quantum mechanics, we analyze the structure generated by unbounded metric operators in a Hilbert space. To that effect, we consider the notions of similarity and quasi-similarity…

Mathematical Physics · Physics 2016-10-24 Jean-Pierre Antoine , Camillo Trapani

In this paper we introduce a new technique for proving norm inequalities in operator ideals with an unitarily invariant norm. Among the well known inequalities which can be proved with this technique are the L\"owner-Heinz inequality,…

Operator Algebras · Mathematics 2008-08-19 Gabriel Larotonda

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

The main aim of this book is to present recent results concerning inequalities for continuous functions of selfadjoint operators on complex Hilbert spaces. It is intended for use by both researchers in various fields of Linear Operator…

Functional Analysis · Mathematics 2012-03-09 Silvestru Sever Dragomir

We establish several operator versions of the classical Aczel inequality. One of operator versions deals with the weighted operator geometric mean and another is related to the positive sesquilinear forms. Some applications including the…

Functional Analysis · Mathematics 2012-03-22 Mohammad Sal Moslehian

Convergence of operators acting on a given Hilbert space is an old and well studied topic in operator theory. The idea of introducing a related notion for operators acting on arying spaces is natural. However, it seems that the first…

Functional Analysis · Mathematics 2014-01-17 Delio Mugnolo , Robin Nittka , Olaf Post

This paper is concerned with paired operators in the context of the Lebesgue Hilbert space on the unit circle and its subspace, the Hardy space. By considering when such operators commute, generalizations of the Brown--Halmos results for…

Functional Analysis · Mathematics 2024-01-01 M. Cristina Câmara , André Guimarães , Jonathan R. Partington

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