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Related papers: Compact composition operators on $H^2$ and Hardy-O…

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In this article, the posinormality and coposinormality of weighted composition-differentiation operators on Hardy space $H^2(\mathbb{D})$ are investigated. It is observed that while a composition-differentiation operator $D_{\phi,n}$ fails…

Functional Analysis · Mathematics 2026-05-11 Gour Hait , Sarita Ojha , Nirupam Ghosh , Riddhick Birbonshi

We give examples of composition operators $C\_\Phi$ on $H^2 (\D^2)$ showing that the condition $\|\Phi \|\_\infty = 1$ is not sufficient for their approximation numbers $a\_n (C\_\Phi)$ to satisfy $\lim\_{n \to \infty} [a\_n (C\_\Phi)…

Functional Analysis · Mathematics 2018-03-05 Daniel Li , Hervé Queffélec , Luis Rodríguez-Piazza

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 investigate the normal weighed composition operators $W_{\psi,\varphi}$ which is $\mathcal{J}-$symmetric, $\mathcal{C}_1-$symmetric and $\mathcal{C}_2-$symmetric on the Hardy space $H^2(\mathbb{D})$ respectively. Firstly,…

Functional Analysis · Mathematics 2019-01-04 Hang Zhou , Ze-Hua Zhou

In this paper, we investigate the lack of compactness of the Sobolev embedding of $H^1(\R^2)$ into the Orlicz space $L^{{\phi}_p}(\R^2)$ associated to the function $\phi_p$ defined by $\phi_p(s):={\rm{e}^{s^2}}-\Sum_{k=0}^{p-1}…

Analysis of PDEs · Mathematics 2013-12-24 Ines Ben Ayed , Mohamed Khalil Zghal

We give embedding theorems for weighted Bergman-Orlicz spaces on the ball and then apply our results to the study of composition operators in this context. As one of the motivations of this work, we show that there exist some weighted…

Functional Analysis · Mathematics 2010-12-06 Stéphane Charpentier

We construct an analytic self-map $\Phi$ of the bidisk ${\mathbb D}^2$ whose image touches the distinguished boundary, but whose approximation numbers of the associated composition operator on $H^2 ({\mathbb D}^2)$ are small in the sense…

Functional Analysis · Mathematics 2019-01-23 Daniel Li , Hervé Queffélec , Luis Rodríguez-Piazza

Extending previous results of Bourdon and Shapiro we characterize the hypercyclic and mixing composition operators $C_{\varphi}$ for the automorphisms of $\mathbb{D}$ on any of the spaces $H^{p}$ with $1\leqslant p<+\infty$.

Functional Analysis · Mathematics 2023-06-02 Zhen Rong

In this paper, we characterize the boundedness and the compactness of weighted composition operators acting on a de Branges-Rovnyak space $\mathcal H(b)$, where the symbol $b$ is a rational function in the unit ball of $H^\infty$ that is…

Complex Variables · Mathematics 2025-12-18 Emmanuel Fricain , Muath Karaki , Javad Mashreghi , Maëva Ostermann

In this paper, we initially study when an anti-linear Toeplitz operator is in the commutant of a composition operator. Primarily, we investigate weighted composition operators $W_{g,\psi}$ commuting with complex symmetric weighted…

Functional Analysis · Mathematics 2024-08-02 Sudip Ranjan Bhuia

We consider the invariant subspace of composition operators on Hardy space $H^p$ where the composition operators corresponding to a function $\varphi$ that is a holomorphic self-map of $\mathbb D$. Firstly, we discuss composition operators…

Functional Analysis · Mathematics 2021-01-21 Tianyu Bai , Junming Liu

We establish very general criteria for the existence of multiplication operators between noncommutative Orlicz spaces $L^{\psi_0}(\tM)$ and $L^{\psi_1}(\tM)$. We then show that these criteria contain existing results, before going on to…

Operator Algebras · Mathematics 2025-03-19 Louis Labuschagne

We investigate composition operators $C_{\Phi}$ on the Hardy-Smirnov space $H^{2}(\Omega)$ induced by analytic self-maps $\Phi$ of an open simply connected proper subset $\Omega$ of the complex plane. When the Riemann map…

Functional Analysis · Mathematics 2025-06-30 V. V. Fávaro , P. V. Hai , D. M. Pellegrino , O. R. Severiano

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

In this paper, the definition of noncommutative Orlicz sequence spaces is given, these spaces generalize the Schatten classes Sp(H). After some relations of trace and norm on this spaces have been researched, one give the criterion of…

Functional Analysis · Mathematics 2019-04-30 Ma Zhenhua , Ji Kui , Li Yucheng

Here, the composition operators on Orlicz spaces with finite ascent and descent as well as infinite ascent and descent are characterized.

Functional Analysis · Mathematics 2016-11-04 Ratan Kr. Giri , Shesadev Pradhan

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

Let $\phi(z)=(\phi_1(z),...,\phi_n(z))$ be a holomorphic self-map of $B_n$ and $\psi(z)$ a holomorphic function on $B_n$, and $H(B_n)$ the class of all holomorphic functions on $B_n$, where $B_n$ is the unit ball of $C^n$, the weight…

Functional Analysis · Mathematics 2013-12-30 Zhong-Shan Fang , Ze-Hua Zhou

In this paper we initiate the study of composition operators on the noncommutative Hardy space $H^2_{\bf ball}$. Several classical results about composition operators (boundedness, norm estimates, spectral properties, compactness,…

Functional Analysis · Mathematics 2011-11-15 Gelu Popescu

For $E$ a Hilbert space, let $\mathcal{H}(E)$ denote the Segal-Bargmann space (also known as the Fock space) over $E$, which is a reproducing kernel Hilbert space with kernel $K(x,y)=\exp(< x,y>)$ for $x,y$ in $E$. If $\phi$ is a mapping on…

Functional Analysis · Mathematics 2011-12-01 Trieu Le