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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…

In this paper, we study the relationship between operator space norm and operator space numerical radius on the matrix space $\mathcal{M}_n(X)$, when $X$ is a numerical radius operator space. Moreover, we establish several inequalities for…

算子代数 · 数学 2021-07-23 Mohammad Sal Moslehian , Mostafa Sattari

We obtain new lower and upper bounds for the numerical radius of a bounded linear operator $A$ on a complex Hilbert space, which refine the existing ones. In particular, if $w(A)$ and $\|A\|$ denote the numerical radius and operator norm of…

泛函分析 · 数学 2026-03-05 Pintu Bhunia , Rukaya Majeed

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…

泛函分析 · 数学 2023-04-03 Raj Kumar Nayak

We present some new upper and lower bounds for the numerical radius of bounded linear operators on a complex Hilbert space and show that these are stronger than the existing ones. In particular, we prove that if $A$ is a bounded linear…

泛函分析 · 数学 2024-08-23 Pintu Bhunia , Suvendu Jana , Kallol Paul

We obtain bounds for the numerical radius of $2 \times 2$ operator matrices which improve on the existing bounds. We also show that the inequalities obtained here generalize the existing ones. As an application of the results obtained here…

泛函分析 · 数学 2024-08-23 Pintu Bhunia , Santanu Bag , Kallol Paul

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.…

泛函分析 · 数学 2023-09-21 Mohammad Sababheh , Hamid Reza Moradi , Mohammad Alomari

We develop upper and lower bounds for the numerical radius of $2\times 2$ off-diagonal operator matrices, which generalize and improve on the existing ones. We also show that if $A$ is a bounded linear operator on a complex Hilbert space…

泛函分析 · 数学 2021-10-07 Pintu Bhunia , Kallol Paul

We present new bounds for the numerical radius of bounded linear operators and $2\times 2$ operator matrices. We apply upper bounds for the numerical radius to the Frobenius companion matrix of a complex monic polynomial to obtain new…

泛函分析 · 数学 2020-01-28 Pintu Bhunia , Santanu Bag , Raj Kumar Nayak , Kallol Paul

Let $A$ be a positive (semidefinite) operator on a complex Hilbert space $\mathcal{H}$ and let $\mathbb{A}=\left(\begin{array}{cc} A & O O & A \end{array}\right).$ We obtain upper and lower bounds for the $A$-Davis-Wielandt radius of…

泛函分析 · 数学 2020-06-11 Aniket Bhanja , Pintu Bhunia , Kallol Paul

Employing the Orlicz functions we extend the Buzano's inequality which is a refinement of the Cauchy-Schwarz inequality. Also using the Orlicz functions we obtain several numerical radius inequalities for a bounded linear operator as well…

泛函分析 · 数学 2024-08-26 Pintu Bhunia , Raj Kumar Nayak

Let ${\mathbb B}(\mathscr H)$ denote the set of all bounded linear operators on a complex Hilbert space ${\mathscr H}$. In this paper, we present some norm inequalities for sums of operators which are a generalization of some recent…

泛函分析 · 数学 2023-10-10 Davood Afraza , Ramatollah Lashkaripoura , Mojtaba Bakherad

The concepts of weighted numerical radius has been defined in recent times. In this article, we obtain several upper bound for weighted numerical radius of operators and $2 \times 2$ operator matrices which generalize and improves some well…

泛函分析 · 数学 2023-02-24 Raj Kumar Nayak

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…

泛函分析 · 数学 2024-08-14 Pintu Bhunia , Kallol Paul , Raj Kumar Nayak

In this paper, we introduce a new semi-norm of operators on a semi-Hilbertian space, which generalizes the A-numerical radius and A-operator semi-norm. We study the basic properties of this semi-norm, including upper and lower bounds for…

泛函分析 · 数学 2024-08-14 Pintu Bhunia , Anirban Sen , Kallol Paul

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…

泛函分析 · 数学 2024-08-13 Pintu Bhunia , Kais Feki , Kallol Paul

In this article, we present new inequalities for the numerical radius of the sum of two Hilbert space operators. These new inequalities will enable us to obtain many generalizations and refinements of some well known inequalities, including…

泛函分析 · 数学 2020-10-27 Hamid Reza Moradi , Mohammad Sababheh

Let $A$ be a bounded linear positive operator on a complex Hilbert space $\mathcal{H}.$ Further, let $\mathcal{B}_A\mathcal{(H)}$ denote the set of all bounded linear operators on $\mathcal{H}$ whose $A$-adjoint exists, and $\mathbb{A}$…

泛函分析 · 数学 2025-08-04 Nirmal Chandra Rout , Debasisha Mishra

We obtain several sharp lower and upper bounds for the Euclidean operator radius of a pair of bounded linear operators defined on a complex Hilbert space. As applications of these bounds we deduce a chain of new bounds for the classical…

泛函分析 · 数学 2024-08-14 Suvendu Jana , Pintu Bhunia , Kallol Paul

If $A,B$ are bounded linear operators on a complex Hilbert space, then % $w(A) \leq \frac{1}{2}\left( \|A\|+\sqrt{r\left(|A||A^*|\right)}\right)$ and $w(AB \pm BA)\leq 2\sqrt{2}\|B\|\sqrt{ w^2(A)-\frac{c^2(\Re (A))+c^2(\Im (A))}{2} },$…

泛函分析 · 数学 2024-08-14 Pintu Bhunia , Kallol Paul