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In this paper, we generalize several Berezin number inequalities involving product of operators. For instance, we show that if $A, B$ are positive operators and $X$ is any operator, then \begin{align*}…

Functional Analysis · Mathematics 2018-05-22 Monire Hajmohamadi , Rahmatollah Lashkaripour , Mojtaba Bakherad

The Berezin symbol $\widetilde{A}$ of an operator $A$ acting on the reproducing kernel Hilbert space ${\mathscr H}={\mathscr H(}\Omega)$ over some (non-empty) set is defined by $\widetilde{A}(\lambda)=\langle…

Functional Analysis · Mathematics 2018-05-04 Mojtaba Bakherad

In this paper, several refinements of the Berezin number inequalities are obtained. We generalize inequalities involving powers of the Berezin number for product of two operators acting on a reproducing kernel Hilbert space $\mathcal…

Functional Analysis · Mathematics 2020-03-24 M. Bakherad , R. Lashkaripour , M. Hajmohamadi , U. Yamanci

We obtain new inequalities involving Berezin norm and Berezin number of bounded linear operators defined on a reproducing kernel Hilbert space $\mathscr{H}.$ Among many inequalities obtained here, it is shown that if $A$ is a positive…

Functional Analysis · Mathematics 2021-12-21 Pintu Bhunia , Kallol Paul , Anirban Sen

In this paper, we establish some upper bounds for Berezin number inequalities including of $2\times 2$ operator matrices and their off-diagonal parts. Among other inequalities, it is shown that if $T=\left[\begin{array}{cc} 0&X, Y&0…

Functional Analysis · Mathematics 2023-01-18 Mojtaba Bakherad , Monire Hajmohamadi , Rahmatollah Lashkaripour , Satyajit Sahoo

For a bounded linear operator $A$ on a reproducing kernel Hilbert space $\mathcal{H}(\Omega)$, with normalized reproducing kernel $\widehat{k}_{\lambda} = \frac{k_{\lambda}}{\lVert k_{\lambda}\lVert}$, the Berezin symbol, Berezin number and…

Functional Analysis · Mathematics 2021-09-21 Mubariz Garayev , Hocine Guediri , Najla Altwaijry

We establish new upper bounds for Berezin number and Berezin norm of operator matrices, which are refinements of the existing bounds. Among other bounds, we prove that if $A=[A_{ij}]$ is an $n\times n$ operator matrix with…

Functional Analysis · Mathematics 2024-08-14 Pintu Bhunia , Anirban Sen , Somdatta Barik , Kallol Paul

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

In this paper, we give the Alzer inequality for Hilbert space operators as follows: Let $A, B$ be two selfadjoint operators on a Hilbert space $\mathcal H$ such that $0 < A, B \le \frac{1}{2}I$, where $I$ is identity operator on $\mathcal…

Functional Analysis · Mathematics 2018-06-29 Ali Morassaei , Farzollah Mirzapour

We give new inequalities for $A$-operator seminorm and $A$-numerical radius of semi-Hilbertian space operators and show that the inequalities obtained here generalize and improve on the existing ones. Considering a complex Hilbert space…

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

We introduce a new class of operators, called Berezin sectorial operators, which generalizes classical sectorial operators. We provide examples on the Hardy-Hilbert space showing that there exist operators that are Berezin sectorial but not…

Functional Analysis · Mathematics 2026-01-07 Saikat Mahapatra , Sweta Mukherjee , Anirban Sen , Riddhick Birbonshi , Kallol Paul

We present several operator and norm inequalities for Hilbert space operators. In particular, we prove that if $A_{1},A_{2},...,A_{n}\in {\mathbb B}({\mathscr H})$, then…

Functional Analysis · Mathematics 2011-01-21 M. Erfanian Omidvar , M. S. Moslehian , A. Niknam

In this note, we introduce a novel norm, termed the $t-$Berezin norm, on the algebra of all bounded linear operators defined on a reproducing kernel Hilbert space $\mathcal{H}$ as $$\|A\|_{t-ber} = \sup_{ \lambda, \mu \in \Omega} \left\{…

Functional Analysis · Mathematics 2025-04-10 Raj Kumar Nayak , Pintu Bhunia

Let $G$ be a Lie group with Lie algebra $\mathfrak g$ and let $\pi$ be a unitary representation of $G$ realized on a reproducing kernel Hilbert space. We use Berezin quantization to study spectral measures associated with operators…

Spectral Theory · Mathematics 2021-04-30 Benjamin Cahen

In this article, we present some new general forms of numerical radius inequalities for Hilbert space operators. The significance of these inequalities follow from the way they extend and refine some known results in this field. Among other…

Functional Analysis · Mathematics 2019-06-21 Mohammad Sababheh , Hamid Reza Moradi

In this article, we establish the Berezin number and Berezin norm inequalities for bounded linear operators on a reproducing kernel Hilbert space using the Moore-Penrose inverse. The inequalities obtained here refine and generalize the…

Functional Analysis · Mathematics 2025-03-25 Saikat Mahapatra , Anirban Sen , Riddhick Birbonshi , Kallol Paul

In this article, we present some new inequalities for numerical radius of Hilbert space operators via convex functions. Our results generalize and improve earlier results by El-Haddad and Kittaneh. Among several results, we show that if…

Functional Analysis · Mathematics 2019-07-16 S. Tafazoli , H. R. Moradi , S. Furuichi , P. Harikrishnan

We present new bounds for the Berezin number inequalities which improve on the existing bounds. We also obtain bounds for the Berezin norm of operators as well as the sum of two operators.

Functional Analysis · Mathematics 2022-02-09 Pintu Bhunia , Anirban Sen , Kallol Paul

We prove some refinements of an inequality due to X. Zhan in an arbitrary complex Hilbert space by using some results on the Heinz inequality. We present several related inequalities as well as new variants of the Corach--Porta--Recht…

Functional Analysis · Mathematics 2012-03-21 Cristian Conde , Mohammad Sal Moslehian , Ameur Seddik

We describe the symbolic calculus of operators on the unit sphere in the complex n-space $\mathbb C^n$ defined by the Berezin quantization. In particular, we derive a explicit formula for the composition of Berezin symbol and with that a…

Classical Analysis and ODEs · Mathematics 2017-02-21 Erik I. Díaz-Ortíz
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