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In this paper, we study the basic properties such as boundedness and compactness of composition operators on discrete analogue of generalized Hardy space defined on a homogeneous rooted tree. Also, we compute the operator norm of…

Functional Analysis · Mathematics 2016-10-03 Perumal Muthukumar , Saminathan Ponnusamy

In this paper, we find complex symmetric composition operators on the classical Hardy space whose symbols are linear-fractional but not automorphic. In doing so, we answer a recent question of Noor, and partially answer the original problem…

Complex Variables · Mathematics 2017-05-17 Sivaram K. Narayan , Daniel Sievewright , Derek Thompson

Let H^2(D) denote the classical Hardy space of the open unit disk D in the complex plane. We obtain descriptions of both the spectrum and essential spectrum of composition operators on H^2(D) whose symbols belong to the class S(2)…

Functional Analysis · Mathematics 2015-01-05 Paul S. Bourdon

We consider composition operators $\mathscr{C}_\varphi$ on the Hardy space of Dirichlet series $\mathscr{H}^2$, generated by Dirichlet series symbols $\varphi$. We prove two different subordination principles for such operators. One…

Functional Analysis · Mathematics 2019-11-13 Ole Fredrik Brevig , Karl-Mikael Perfekt

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

This paper studies the behaviour of iterates of weighted composition operators acting on spaces of analytic functions, with particular emphasis on the Hardy space $H^2$. Questions relating to uniform, strong and weak convergence are…

Functional Analysis · Mathematics 2020-02-11 I. Chalendar , J. R. Partington

In this paper we characterize some basic properties of composition operators on the spaces of harmonic Bloch functions. First we provide some equivalent conditions for boundedness and compactness of composition operators. Then by using…

Functional Analysis · Mathematics 2018-12-27 Y. Estaremi , S. Esmaili , A. Ebadian

To appear in J. Functional Analysis

Functional Analysis · Mathematics 2008-06-27 Pascal Lefevre , Daniel Li , Herve Queffelec , Luis Rodriguez-Piazza

In this study we consider the approximation numbers of differences of composition operators acting on the Hardy-Hilbert space H 2 (D). We obtain both upper and lower bounds for these approximation numbers and by applying these general…

Functional Analysis · Mathematics 2025-09-25 Frédéric Bayart , Clifford Gilmore , Sibel Sahin

We show that the weighted Bergman-Orlicz space $A\_{\alpha}^{\psi}$ coincides with some weighted Banach space of holomorphic functions if and only if the Orlicz function $\psi$ satisfies the so-called $\Delta^{2}$--condition. In addition we…

Complex Variables · Mathematics 2018-01-24 Stéphane Charpentier

We give a new proof of the existence of a surjective symbol whose associated composition operator on H 2 (D) is in all Schatten classes, with the improvement that its approximation numbers can be, in some sense, arbitrarily small. We show,…

Functional Analysis · Mathematics 2018-11-14 Daniel Li , Hervé Queffélec , Luis Rodríguez-Piazza

H. J. Schwartz proved in his thesis (1969) that a nonzero bounded operator on Hardy spaces $(H^p, 1\leq p\leq\infty)$ is almost multiplicative if and only if it is a composition operator. But, his proof has a gap. In this article, we show…

Functional Analysis · Mathematics 2025-12-08 Kanha Behera , Junming Liu , P. Muthukumar

This paper aims to study the boundedness and compactness of composition operators from model spaces to the Hardy Hilbert spaces in the upper half-plane. Consequently, we investigate the boundedness and compactness of composition operators…

Functional Analysis · Mathematics 2026-05-13 Bharti Garg , Subhankar Mahapatra , Santanu Sarkar

In this paper, we consider the sum of weighted composition operator $C_{\psi_{0},\varphi_{0}}$ and the weighted composition--differentiation operator $D_{\psi_{n},\varphi_{n},n}$ on the Hardy and weighted Bergman spaces. We describe the…

Functional Analysis · Mathematics 2021-08-13 Mahsa Fatehi

In this paper we investigate the numerical ranges of composition operators whose symbols are elliptic automorphisms of finite orders, on the Hilbert Hardy space $H^2(D)$.

Functional Analysis · Mathematics 2023-02-22 Yong-Xin Gao , Ze-Hua Zhou

We define Hardy spaces $\mathcal{H}^p$ for quasiregular mappings in the plane, and show that for a particular class of these mappings many of the classical properties that hold in the classical setting of analytic mappings still hold. This…

Complex Variables · Mathematics 2020-11-05 Tomasz Adamowicz , María J. González

Let $\varphi_j$, $j=1,2, \dots, N$, be holomorphic self-maps of the unit disk $\mathbb{D}$ of $\mathbb{C}$. We prove that the compactness of a linear combination of the composition operators $C_{\varphi_j}: f\mapsto f\circ\varphi_j$ on the…

Complex Variables · Mathematics 2024-10-15 Evgueni Doubtsov , Dmitry V. Rutsky

In this paper, we investigate the conditions under which the Toeplitz Composition operator on the Hardy space $\mathcal{H}^2$ becomes complex symmetric with respect to a certain conjugation. We also study various normality conditions for…

Functional Analysis · Mathematics 2019-12-10 Anuradha Gupta , Aastha Malhotra

In this paper, we investigate necessary and sufficient conditions on the boundedness of composition operators on the Orlicz-Morrey spaces. The results of boundedness include Lebesgue and generalized Morrey spaces as special cases. Further,…

Functional Analysis · Mathematics 2024-04-16 Masahiro Ikeda , Isao Ishikawa , Ryota Kawasumi

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