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If $b$ is an inner function, then composition with $b$ induces an endomorphism, $\beta$, of $L^\infty(\mathbb{T})$ that leaves $H^\infty(\mathbb{T})$ invariant. We investigate the structure of the endomorphisms of $B(L^2(\mathbb{T}))$ and…

Functional Analysis · Mathematics 2012-05-09 Dennis Courtney , Paul S. Muhly , Samuel W. Schmidt

In this paper, we study 2-complex symmetric composition operators with the conjugation $J$ on the Hardy space $H^2$. More precisely, we obtain the necessary and sufficient condition for the composition operator $C_\phi$ to be 2-complex…

Complex Variables · Mathematics 2021-10-22 Lian Hu , Songxiao Li , Rong Yang

We compare the compactness of composition operators on $H^2$ and on Orlicz-Hardy spaces $H^\Psi$. We show in particular that exists an Orlicz function $\Psi$ such that $H^{3+\eps} \subseteq H^\Psi \subseteq H^3$ for every $\eps >0$, and a…

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

In this paper, we investigate the complex symmetric structure of generalized weighted composition operators $D_{m,\psi,\varphi}$ on the weighted Hardy space $H^2(\beta)$. We obtain explicit conditions for $ D_{m,\psi,\varphi}$ to be complex…

Functional Analysis · Mathematics 2022-04-25 Lian Hu , Songxiao Li , Rong Yang

The boundedness and compactness of weighted composition operators on the Hardy space ${\mathcal H}^2$ of the unit disc is analysed. Particular reference is made to the case when the self-map of the disc is an inner function. Schatten-class…

Functional Analysis · Mathematics 2009-07-15 Eva A. Gallardo-Gutiérrez , Romesh Kumar , Jonathan R. Partington

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 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

Let $\varphi$ be a holomorphic self-map of a bounded homogeneous domain $D$ in $\mathbb{C}^n$. In this work, we show that the composition operator $C_\varphi: f\mapsto f\circ \varphi$ is bounded on the Bloch space $\mathcal{B}$ of the…

Functional Analysis · Mathematics 2022-07-27 Robert F. Allen , Flavia Colonna

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

In this article, we characterize the Beurling and Model subspaces of the Hardy-Hilbert space $H^2(\mathbb{D})$ invariant under the composition operator $C_{\phi_a}f=f\circ\phi_a$, where $\phi_a(z) = az + 1 - a$ for $a \in (0,1)$ is an…

Functional Analysis · Mathematics 2024-06-17 Ben Hur Eidt , S. Waleed Noor

Our study is focused on the dynamics of weighted composition operators defined on a locally convex space $E\hookrightarrow (C(X),\tau_p)$ with $X$ being a topological Hausdorff space containing at least two different points and such that…

Functional Analysis · Mathematics 2019-02-22 María José Beltrán , Enrique Jordá , Marina Murillo-Arcila

In this paper we prove an invertibility criterion for certain operators which is given as a linear algebraic combination of Toeplitz operators and Fourier multipliers acting on the Hardy space of the unit disc. Very similar to the case of…

Functional Analysis · Mathematics 2017-09-25 Uğur Gül , Beyaz Başak Koca

Here we consider when the difference of two composition operators is compact on the weighted Dirichlet spaces $\mathcal{D}_\alpha$. Specifically we study differences of composition operators on the Dirichlet space $\mathcal{D}$ and $S^2$,…

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

We consider the Banach space $H^\infty_{\mathrm{ap}}(\mathbb{C}_0)$ of bounded analytic functions on the open right half-plane $\mathbb{C}_0$ that are almost periodic on some smaller half-plane, as well as the subspace…

Functional Analysis · Mathematics 2025-12-08 Viktor Andersson

In this paper, we prove that if $T$ is diskcyclic operator then the closed unit disk multiplied by the union of the numerical range of all iterations of $T$ is dense in $\mathcal H$. Also, if $T$ is diskcyclic operator and $|\lambda|\le 1$,…

Functional Analysis · Mathematics 2015-04-24 Nareen Bamerni , Adem Kılıçman

For $\alpha > 0$ we consider the operator $K_\alpha \colon \ell^2 \to \ell^2$ corresponding to the matrix \[\left(\frac{(nm)^{-\frac{1}{2}+\alpha}}{[\max(n,m)]^{2\alpha}}\right)_{n,m=1}^\infty.\] By interpreting $K_\alpha$ as the inverse of…

Functional Analysis · Mathematics 2024-07-09 Ole Fredrik Brevig , Karl-Mikael Perfekt , Alexander Pushnitski

In this note we give a new sufficient condition for the boundedness of the composition operator on the Dirichlet-type space on the disc, via a two dimensional change of variables formula. With the same formula, we characterise the bounded…

Complex Variables · Mathematics 2025-03-18 Athanasios Beslikas

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

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

In this note, we completely characterize complex symmetric weighted composition differentiation operator on the Hardy space $H^2$ with respect to the conjugation operator $C_{\lambda,\alpha}$. Meanwhile, the normal and self-adjoint of the…

Functional Analysis · Mathematics 2020-11-17 Junming Liu , Saminathan Ponnusamy , Huayou Xie
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