Composition operators on Hardy-Smirnov spaces

Fuente: arXiv
Gespeichert in:
Bibliographische Detailangaben
Hauptverfasser: Fávaro, V. V., Hai, P. V., Pellegrino, D. M., Severiano, O. R.
Format: Preprint
Veröffentlicht: 2021
Schlagworte:
Online-Zugang:
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
_version_ 1866913915155251200
author Fávaro, V. V.
Hai, P. V.
Pellegrino, D. M.
Severiano, O. R.
author_facet Fávaro, V. V.
Hai, P. V.
Pellegrino, D. M.
Severiano, O. R.
contents We investigate composition operators $C_Φ$ on the Hardy-Smirnov space $H^{2}(Ω)$ induced by analytic self-maps $Φ$ of an open simply connected proper subset $Ω$ of the complex plane. When the Riemann map $τ:\mathbb{U}\rightarrowΩ$ used to define the norm of $H^{2}(Ω)$ is a linear fractional transformation, we characterize the composition operators whose adjoints are composition operators. As applications of this fact, we provide a new proof for the adjoint formula discovered by Gallardo-Gutiérrez and Montes-Rodríguez and we give a new approach to describe all Hermitian and unitary composition operators on $H^{2}(Ω).$ Additionally, if the coefficients of $τ$ are real, we exhibit concrete examples of conjugations and describe the Hermitian and unitary composition operators which are complex symmetric with respect to specific conjugations on $H^{2}(Ω).$ We finish this paper showing that if $Ω$ is unbounded and $Φ$ is a non-automorphic self-map of $Ω$ with a fixed point, then $C_Φ$ is never complex symmetric on $H^{2}(Ω).$
format Preprint
id arxiv_https___arxiv_org_abs_2111_10609
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Composition operators on Hardy-Smirnov spaces
Fávaro, V. V.
Hai, P. V.
Pellegrino, D. M.
Severiano, O. R.
Functional Analysis
47B33, 47B32, 47B99
We investigate composition operators $C_Φ$ on the Hardy-Smirnov space $H^{2}(Ω)$ induced by analytic self-maps $Φ$ of an open simply connected proper subset $Ω$ of the complex plane. When the Riemann map $τ:\mathbb{U}\rightarrowΩ$ used to define the norm of $H^{2}(Ω)$ is a linear fractional transformation, we characterize the composition operators whose adjoints are composition operators. As applications of this fact, we provide a new proof for the adjoint formula discovered by Gallardo-Gutiérrez and Montes-Rodríguez and we give a new approach to describe all Hermitian and unitary composition operators on $H^{2}(Ω).$ Additionally, if the coefficients of $τ$ are real, we exhibit concrete examples of conjugations and describe the Hermitian and unitary composition operators which are complex symmetric with respect to specific conjugations on $H^{2}(Ω).$ We finish this paper showing that if $Ω$ is unbounded and $Φ$ is a non-automorphic self-map of $Ω$ with a fixed point, then $C_Φ$ is never complex symmetric on $H^{2}(Ω).$
title Composition operators on Hardy-Smirnov spaces
topic Functional Analysis
47B33, 47B32, 47B99
url https://arxiv.org/abs/2111.10609