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We study the intertwining relations between analytic Toeplitz operators induced on the Hardy space H^2 by analytic functions bounded on the open unit disc. Our work centers on the connection between intertwining between the Toeplitz…

Functional Analysis · Mathematics 2009-03-31 Paul S. Bourdon , Joel H. Shapiro

The boundedness and compactness of Toeplitz operator from $A_\omega^p$ to $A_\omega^q$ with doubling weights $\omega$ are studied in this paper. The characterizations of Schatten class Toeplitz operators and Volterra operators on…

Complex Variables · Mathematics 2019-09-24 Juntao Du , Songxiao Li

The Invariant Subspace Problem (ISP) for Hilbert spaces asks if every bounded linear operator has a non-trivial closed invariant subspace. Due to the existence of universal operators (in the sense of Rota), the ISP may be solved by…

Functional Analysis · Mathematics 2020-09-16 Marcos Ferreira , S. Waleed Noor

Let $X$ be a Banach function space over the unit circle such that the Riesz projection $P$ is bounded on $X$ and let $H[X]$ be the abstract Hardy space built upon $X$. We show that the essential norm of the Toeplitz operator $T(a):H[X]\to…

Functional Analysis · Mathematics 2024-08-27 Oleksiy Karlovych , Eugene Shargorodsky

Motivated by the canonical decomposition of contractions on Hilbert spaces, we investigate when contractive Toeplitz operators on vector-valued Hardy spaces on the unit disc admit a non-zero reducing subspace on which its restriction is…

Functional Analysis · Mathematics 2024-02-02 E. K. Narayanan , Srijan Sarkar

In this paper we study the essential spectra of the Toeplitz operator on the Hardy space $H^1$. We give a counterexample to show that the Toeplitz operator with symbol is not Fredholm, which gives a counterexample to the conjecture by J.A.…

Functional Analysis · Mathematics 2025-03-12 Hua Liu , Xinyang Zhang

Our goal is to compare various results for Toeplitz $T$ and Hankel $H$ operators. We consider semibounded operators and find necessary and sufficient conditions for their quadratic forms to be closable. This property allows one to define…

Functional Analysis · Mathematics 2017-11-08 D. R. Yafaev

We study subnormal Toeplitz operators on the vector-valued Hardy space of the unit circle, along with an appropriate reformulation of P.R. Halmos's Problem 5: Which subnormal block Toeplitz operators are either normal or analytic? We extend…

Functional Analysis · Mathematics 2012-07-16 Raul Curto , In Sung Hwang , Woo Young Lee

Let $\Gamma$ be a rectifiable Jordan curve, let $X$ and $Y$ be two reflexive Banach function spaces over $\Gamma$ such that the Cauchy singular integral operator $S$ is bounded on each of them, and let $M(X,Y)$ denote the space of pointwise…

Functional Analysis · Mathematics 2017-08-07 Alexei Yu. Karlovich

We study the boundedness and compactness properties of the generalized integration operator $T_{g,a}$ when it acts between distinct Hardy spaces in the unit disc of the complex plane. This operator has been introduced by the first author in…

Complex Variables · Mathematics 2024-06-10 Nikolaos Chalmoukis , Georgios Nikolaidis

In this paper, we study Toeplitz operators on the weighted harmonic Bergman spaces with nonnegative symbols, the weights we choose here are Muckenhoupt A_2 weights. Results obtained include characterizations of bounded Toeplitz operators,…

Functional Analysis · Mathematics 2018-11-14 Zipeng Wang , Xianfeng Zhao

In this article, we introduce a new class of conjugations in the scalar valued Hardy space $H^2_{\mathbb{C}}(\mathbb{D})$ and provide a characterization of a complex symmetric Toeplitz operator $T_{\phi}$ with respect to these newly…

Functional Analysis · Mathematics 2021-08-17 Arup Chattopadhyay , Soma Das , Chandan Pradhan , Srijan Sarkar

Motivated by the work of Nazarov and Shapiro on the unit disk, we study asymptotic Toeplitzness of composition operators on the Hardy space of the unit sphere in C^n. We extend some of their results but we also show that new phenomena…

Functional Analysis · Mathematics 2013-08-12 Zeljko Cuckovic , Trieu Le

We define positive Toeplitz operators between weighted harmonic Bloch spaces $b^\infty_\alpha$ on the unit ball of $\mathbb{R}^n$ for the full range of parameter $\alpha\in\mathbb{R}$. We give characterizations of bounded and compact…

Complex Variables · Mathematics 2023-05-22 Ömer Faruk Doğan

This paper is about the operators defined between K\"othe spaces whose associated matrix is a Hankel matrix. After demonstrating how these operators are defined, the conditions for continuity and compactness of these operators are…

Functional Analysis · Mathematics 2024-10-01 Nazlı Doğan

Let $\mathcal{H}$ be a separable Hilbert space and let $A^{2}_{\varphi}(\mathcal{H})$ be the $\mathcal{H}$-valued Bergman spaces with exponential weights. In the present paper, we give the complete characterizations for the boundedness and…

Functional Analysis · Mathematics 2023-05-29 Jian-xiang Dong , Yu-feng Lu

Let $m \geq 1$ be an integer and let $H_m(\mathbb B)$ be the analytic functional Hilbert space on the unit ball $\mathbb B \subset \mathbb C^n$ given by the reproducing kernel $K_m(z,w) = (1 - \langle z,w \rangle)^{-m}$. We prove that…

Functional Analysis · Mathematics 2017-10-31 Jörg Eschmeier , Sebastian Langendörfer

In the recent paper by Mark C. Ho (2014) the notion of a $\lambda$-Toeplitz operator on the Hardy space $H^2(\mathbb{T})$ over the one-dimensional torus $\mathbb{T}$ was introduced and it was shown (under the supplementary condition) that…

Functional Analysis · Mathematics 2019-02-26 A. R. Mirotin

We extend to multilinear Hankel operators the fact that some truncations of bounded Hankel operators are bounded. We prove and use a continuity property of bilinear Hilbert transforms on products of Lipschitz spaces and Hardy spaces.

Complex Variables · Mathematics 2016-09-07 Aline Bonami , Sandrine Grellier , Mohammad Kacim

In this article, we completely classify invariant subspaces of finite-rank perturbations of a class of Toeplitz operators on vector-valued Hardy spaces. As a consequence, in the vector-valued setting, we characterize invariant and almost…

Functional Analysis · Mathematics 2026-02-25 Arshad Khan , Sneh Lata , Dinesh Singh