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Let $\mathbb{B}$ be the unit ball of a complex Banach space $X$. In this paper, we will generalize the Bloch-type spaces and the little Bloch-type spaces to the open unit ball $\mathbb{B}$ by using the radial derivative. Next, we define an…

Complex Variables · Mathematics 2018-04-23 Hidetaka Hamada

For any real $\beta$ let $H^2_\beta$ be the Hardy-Sobolev space on the unit disc $\mathbb{D}$. $H^2_\beta$ is a reproducing kernel Hilbert space and its reproducing kernel is bounded when $\beta>1/2$. In this paper, we characterize that for…

Complex Variables · Mathematics 2022-07-29 Guangfu Cao , Li He , Sui Huang

We characterize the strictly increasing symbols $\varphi:\mathbb{N}_0\longrightarrow\mathbb{N}_0$ whose composition operators $C_{\varphi}$ satisfy the Frequent Hypercyclicity Criterion on the little Lipschitz space…

Functional Analysis · Mathematics 2026-03-31 Antoni López-Martínez

The main purpose of this paper is to investigate characterizations of composition operators on Bloch and Hardy type spaces. Initially, we use general doubling weights to study the composition operators from harmonic Bloch type spaces on the…

Complex Variables · Mathematics 2023-12-11 Shaolin Chen , Hidetaka Hamada

We study the compactness of composition operators on the Bergman spaces of certain bounded convex domains in $\mathbb{C}^n$ with non-trivial analytic discs contained in the boundary. As a consequence we characterize that compactness of the…

Complex Variables · Mathematics 2022-04-18 Timothy G. Clos

In this paper we investigate composition operators on discrete spaces. We establish the classification of underlying graphs of such operators. For one class of such graphs, namely graphs with one cycle, we obtain a characterization of…

Functional Analysis · Mathematics 2024-07-30 Michał Buchała

We provide a boundedness criterion for the integral operator $S_{\varphi}$ on the fractional Fock-Sobolev space $F^{s,2}(\mathbb C^n)$, $s\geq 0$, where $S_{\varphi}$ (introduced by Kehe Zhu) is given by \begin{eqnarray*} S_{\varphi}F(z):=…

Complex Variables · Mathematics 2021-01-12 Guangfu Cao , Li He , Ji Li , Minxing Shen

We investigate the relationship between the complex symmetry of composition operators $C_{\phi}f=f\circ \phi$ induced on the classical Hardy space $H^2(\mathbb{D})$ by an analytic self-map $\phi$ of the open unit disk $\mathbb{D}$ and its…

Functional Analysis · Mathematics 2020-09-17 S. Waleed Noor , Osmar R. Severiano

We observe that local embedding problems for certain Hardy and Bergman spaces of Dirichlet series are equivalent to boundedness of a class of composition operators. Following this, we perform a careful study of such composition operators…

Complex Variables · Mathematics 2019-11-05 Frédéric Bayart , Ole Fredrik Brevig

This paper gives some simple estimates of the essential norm for the difference of composition operators induced by $\phi$ and $\psi$ acting on bounded function space in the unit polydiscs $U^n$, where $\phi(z)$ and $\psi(z)$be holomorphic…

Functional Analysis · Mathematics 2007-09-11 Zhongshan Fang , Zehua Zhou

In \cite{CO-Tp-spaces}, the present authors initiated the study of composition operators on discrete analogue of generalized Hardy space $\mathbb{T}_{p}$ defined on a homogeneous rooted tree. In this article, we give equivalent conditions…

Complex Variables · Mathematics 2020-04-08 Perumal Muthukumar , Saminathan Ponnusamy

We study invertibility of bounded composition operators of Sobolev spaces. The problem is closely connected with the theory of mappings of finite distortion. If a homeomorphism $\varphi$ of Euclidean domains $D$ and $D'$ generates by the…

Complex Variables · Mathematics 2009-03-24 V. Gol'dshtein , A. Ukhlov

Let $S(\mathbb{D})$ be the collection of all holomorphic self-maps on $\mathbb{D}$ of the complex plane $\mathbb{C}$, and $C_{\varphi}$ the composition operator induced by $\varphi\in S(\mathbb{D})$. We obtain that there are no hypercyclic…

Functional Analysis · Mathematics 2017-03-30 Yu-Xia Liang , Ze-Hua Zhou

Suppose $n\geq 3$ and let $B$ be the open unit ball in $\mathbb{R}^n$. Let $\varphi: B\to B$ be a $C^2$ map whose Jacobian does not change sign, and let $\psi$ be a $C^2$ function on $B$. We characterize bounded weighted composition…

Complex Variables · Mathematics 2017-08-18 Pengyan Hu , Congwen Liu , Taishun Liu , Lifang Zhou

In this article, we study the complex symmetry of compositions operators $C_{\phi}f=f\circ \phi$ induced on weighted Bergman spaces $A^2_{\beta}(\mathbb{D}),\ \beta\geq -1,$ by analytic self-maps of the unit disk. One of ours main results…

Functional Analysis · Mathematics 2025-06-30 Osmar R. Severiano

Composition operators with analytic symbols on some reproducing kernel Hilbert spaces of entire functions on a complex Hilbert space are studied. The questions of their boundedness, seminormality and positivity are investigated. It is…

Functional Analysis · Mathematics 2016-10-17 Jan Stochel , Jerzy B. Stochel

In this paper, we study composition operators on Hilbert space of complex-valued harmonic functions. In particular, we explore isometries, the type of self-map that generate bounded composition operator, and characterize the boundedness of…

Functional Analysis · Mathematics 2025-03-14 Tseganesh Getachew Gebrehana , Hunduma Legesse Geleta

By a theorem of Gordon and Hedenmalm, $\varphi$ generates a bounded composition operator on the Hilbert space $\mathscr{H}^2$ of Dirichlet series $\sum_n b_n n^{-s}$ with square-summable coefficients $b_n$ if and only if $\varphi(s)=c_0…

Functional Analysis · Mathematics 2015-02-23 Hervé Queffélec , Kristian Seip

We investigate the isometric composition operators on the analytic Besov spaces. For $1<p<2$ we show that an isometric composition operator is induced only by a rotation of the disk. For $p>2$, we extend previous work on the subject.…

Functional Analysis · Mathematics 2022-07-27 Robert F. Allen , Katherine Heller , Matthew A. Pons

If $\psi$ is analytic on the open unit disk $\mathbb{D}$ and $\varphi$ is an analytic self-map of $\mathbb{D}$, the weighted composition operator $C_{\psi,\varphi}$ is defined by $C_{\psi,\varphi}f(z)=\psi(z)f (\varphi (z))$, when $f$ is…

Functional Analysis · Mathematics 2016-02-11 Mahsa Fatehi , Mahmood Haji Shaabani
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