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In this paper, we compute the iterated Aluthge transforms $\widetilde{C_\phi}^{(n)}$ of the composition operator $C_\phi$ on the weighted Bergman spaces $\mathcal{A}_\alpha^2(\mathbb{D})$, where $\phi(z)=az+(1-a)$ for $0<a<1$. Also, we…

Functional Analysis · Mathematics 2026-05-01 Sudeshna Lahiri , Sarita Ojha , Riddhick Birbonshi

In this paper we show that a composition operator $C_\varphi$ cannot be complex symmetric on Hardy-Hilbert space $H^2(D)$ when $\varphi$ is an elliptic automorphism of order $3$ and not a rotation. This completes the project of finding all…

Functional Analysis · Mathematics 2016-08-02 Yong-Xin Gao , Ze-Hua Zhou

In this paper, we study the complex symmetry of weighted composition-differentiation operator $D_{n, \psi, \phi}$ on weighted Bergman spaces $\mathcal{A}^2_{\alpha}$ with respect to the conjugation $C_{\mu, \eta}$ for $\mu, \eta \in \{z\in…

Complex Variables · Mathematics 2023-01-23 Vasudevarao Allu , Himadri Halder , Subhadip Pal

A general method for estimating the approximation numbers of composition operators on $\Ht$, using finite-dimensional model subspaces, is studied and applied in the case when the symbol of the operator maps the unit disc to a domain whose…

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

In this paper we will show how the boundedness condition for the weighted composition operators on a class of spaces of analytic functions on the open right complex half-plane called Zen spaces (which include the Hardy spaces and weighted…

Functional Analysis · Mathematics 2017-02-09 Andrzej S. Kucik

In this paper we propose a different (and equivalent) norm on $S^{2} ({\mathbb{D}})$ which consists of functions whose derivatives are in the Hardy space of unit disk. The reproducing kernel of $S^{2}({\mathbb{D}})$ in this norm admits an…

Functional Analysis · Mathematics 2018-08-31 Caixing Gu , Shuaibing Luo

In this paper, we investigate the boundedness, compactness, essential norm and the Schatten class of weighted composition operators $uC_\varphi$ on Bergman type spaces $A_\omega^p $ with double weight $\omega$. Let $X=\{u\in H(D):…

Complex Variables · Mathematics 2018-11-06 Juntao Du , Songxiao Li , Yecheng Shi

We first obtain a simpler proof of the main results in [IEOT, {\bf 93}(2021), 17], which characterized the bounded and compact differences $C_{u,\varphi}-C_{v,\psi}$ of two weighted composition operators acting from…

Functional Analysis · Mathematics 2025-07-29 Jiaoye Du , Cezhong Tong , Zicong Yang

For $0<p<\infty $ and $\alpha >-1$ the space of Dirichlet type $\mathcal D^p_\alpha $ consists of those functions $f$ which are analytic in the unit disc $\mathbb D$ and satisfy $\int_{\mathbb D}(1-| z| )^\alpha| f^\prime (z)|…

Complex Variables · Mathematics 2018-04-12 Petros Galanopoulos , Daniel Girela , María Auxiliadora Márquez

We study the hypercyclic, supercyclic and cyclic properties of composition operator $C_{\phi}$ on the Segal-Bargmann space $\mathscr{H}(\mathscr{E})$, where $\phi (z)=Az+b$, $A\in \mathcal{B}(\mathscr{E})$, $b\in \mathscr{E}$ with…

Functional Analysis · Mathematics 2021-03-23 G. Ramesh , B. Sudip ranjan , D. Venku Naidu

We give a new proof that every linear fractional map of the unit ball induces a bounded composition operator on the standard scale of Hilbert function spaces on the ball, and obtain norm bounds analogous to the standard one-variable…

Functional Analysis · Mathematics 2007-07-24 Michael T. Jury

Suppose $\varphi$ is a holomorphic self map of the unit disk and $C_\varphi$ is a composition operator with symbol $\varphi$ that fixes the origin and $0<|\varphi'(0)|<1$. This work explores sufficient conditions that ensure all holomorphic…

Complex Variables · Mathematics 2017-08-07 Bhupendra Paudyal

This paper seeks to extend the theory of composition operators on analytic functional Hilbert spaces from analytic symbols to quasiconformal ones. The focus is the boundedness but operator-theoretic questions are discussed as well. In…

Functional Analysis · Mathematics 2018-04-17 Xiang Fang , Kunyu Guo , Zipeng Wang

The algebra of Dirichlet series $\mathcal{A}(\mathcal{C}_{+})$ consists on those Dirichlet series convergent in the right half-plane $\mathcal{C}_{+}$ and which are also uniformly continuous there. This algebra was recently introduced by…

Functional Analysis · Mathematics 2023-12-01 Manuel D. Contreras , Carlos Gómez-Cabello , Luis Rodríguez-Piazza

Recently, Charpentier showed that there exist holomorphic functions $f$ in the unit disk such that, for any proper compact subset $K$ of the unit circle, any continuous function $\phi$ on $K$ and any compact subset $L$ of the unit disk,…

Complex Variables · Mathematics 2021-06-09 Konstantinos Maronikolakis

Let $ T:[0,1]\to[0,1] $ be an expanding Markov map with a finite partition. Let $ \mu_\phi $ be the invariant Gibbs measure associated with a H\"older continuous potential $ \phi $. In this paper, we investigate the size of the uniform…

Dynamical Systems · Mathematics 2022-09-27 Yubin He , Lingmin Liao

Very recently, Bo\v{z}in and Karapetrovi\'c solved a conjecture by proving that the norm of the Hilbert matrix operator $\mathcal{H}$ on the Bergman space $A^p$ is equal to $\frac{\pi}{\sin(\frac{2\pi}{p})}$ for $2 < p < 4.$ In this article…

Functional Analysis · Mathematics 2018-05-22 Mikael Lindström , Santeri Miihkinen , Niklas Wikman

We consider rank one perturbations $A_\alpha=A+\alpha(\cdot,\varphi)\varphi$ of a self-adjoint operator $A$ with cyclic vector $\varphi\in\mathcal H_{-1}(A)$ on a Hilbert space $\mathcal H$. The spectral representation of the perturbed…

Functional Analysis · Mathematics 2010-07-08 Constanze Liaw , Sergei Treil

Let $\varphi$ be a self-map of the unit disk and let $C_\varphi$ denote the composition operator acting on the standard Dirichlet space $\mathcal{D}$. A necessary condition for compactness of a difference of two bounded composition…

Complex Variables · Mathematics 2014-09-29 Małgorzata Michalska , Andrzej Michalski

In this paper we investigate the following problem: when a bounded analytic function $\phi$ on the unit disk $\mathbb{D}$, fixing 0, is such that $\{\phi^n : n = 0, 1, 2, . . . \}$ is orthogonal in $\mathbb{D}$?, and consider the problem of…

Functional Analysis · Mathematics 2007-05-23 Gerardo A. Chacon , Gerardo R. Chacon , Jose Gimenez