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In this paper we consider composition operators on Harmonic-Bloch type spaces and we compute the spectrum of composition operators. Also, we characterize isometric composition operators on harmonic Bloch type spaces.

Functional Analysis · Mathematics 2022-02-15 Y. Estaremi , A. Ebadian , S. Esmaeili

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 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

Let $\varphi$ be a linear fractional self-map of the open unit disk $\mathbb{D}$ and $H^2$ the Hardy space of analytic functions on $\mathbb{D}$. The goal of this article is to characterize the linear fractional composition operators…

Functional Analysis · Mathematics 2018-09-26 S. Waleed Noor

We generalize, on one hand, some results known for composition operators on Hardy spaces to the case of Hardy-Orlicz spaces $H^\Psi$: construction of a "slow" Blaschke product giving a non-compact composition operator on $H^\Psi$;…

Functional Analysis · Mathematics 2010-01-20 Pascal Lefèvre , Daniel Li , Hervé Queffélec , Luis Rodriguez-Piazza

We study composition operators on spaces of holomorphic Lipschitz functions defined on the open unit ball of a complex Banach space. Our approach is based on the linearization of the symbol through the holomorphic Lipschitz-free spaces,…

Functional Analysis · Mathematics 2026-05-21 Verónica Dimant , Luis C. García-Lirola , Juan Guerrero-Viu , Antonín Procházka

Let $B_{n}$ be the unit ball in the complex vector space $\mathbb{C}^{n}$, and let $\varphi: B_{n}\rightarrow B_{n}$ be a holomorphic mapping. In this paper, we characterize those symbols $\varphi$ such that composition operators…

Complex Variables · Mathematics 2025-05-14 H. Chen , X. Zhang

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

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 the present paper, we study the composition operators acting on weighted Hardy spaces of polynomial growth, which are concerned with norms, spectra and (semi-)Fredholmness. Firstly, we estimate the norms of the composition operators with…

Functional Analysis · Mathematics 2023-02-17 Bingzhe Hou , Chunlan Jiang

We give estimates for the approximation numbers of composition operators on $H^2$, in terms of some modulus of continuity. For symbols whose image is contained in a polygon, we get that these approximation numbers are dominated by $\e^{- c…

Functional Analysis · Mathematics 2012-06-07 Daniel Li , Hervé Queffélec , Luis Rodriguez-Piazza

We give a necessary and sufficient condition for a holomorphic self-map $\phi$ of the tridisc to induce a bounded composition operator on the associated Hardy space. This condition depends on the behaviour of the first and the second…

Functional Analysis · Mathematics 2023-12-06 Frédéric Bayart

The main purpose of this paper is to discuss Hardy type spaces, Bloch type spaces and the composition operators of complex-valued harmonic functions. We first establish a sharp estimate of the Lipschitz continuity of complex-valued harmonic…

Complex Variables · Mathematics 2022-07-11 Shaolin Chen , Hidetaka Hamada , Jian-Feng Zhu

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

Let $\varphi$ be a holomorphic map which is a symbol of a bounded composition operator $C_\varphi$ acting on the Hardy-Hilbert space of Dirichlet series. We find a K\"onigs map for $\varphi$. We then deduce several applications on…

Functional Analysis · Mathematics 2024-07-01 Frédéric Bayart , Xingxing Yao

We investigate the bounded composition operators induced by linear fractional self-maps of the right half-plane $\mathbb{C}_+$ on the Hardy space $H^2(\mathbb{C}_+).$ We completely characterize which of these operators are cohyponormal and…

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

Finite-dimensional model spaces are quotient spaces of the Hardy space on the open unit disc, determined by finite Blaschke products. Composition operators, on the other hand, act by composing Hardy space functions with analytic self-maps…

Functional Analysis · Mathematics 2025-09-22 P. Muthukumar , Jaydeb Sarkar , Batzorig Undrakh

We first characterize those composition operators that are essentially normal on the weighted Bergman space $A^2_s(D)$ for any real $s>-1$, where induced symbols are automorphisms of the unit disk $D$. Using the same technique, we…

Complex Variables · Mathematics 2014-08-20 Liangying Jiang , Caiheng Ouyang , Ruhan Zhao

We establish endpoint bounds on a Hardy space $H^1$ for a natural class of multiparameter singular integral operators which do not decay away from the support of rectangular atoms. Hence the usual argument via a Journ\'e-type covering lemma…

Classical Analysis and ODEs · Mathematics 2018-03-06 Odysseas Bakas , Eric Latorre , Diana Cristina Rincón Martínez , James Wright

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