Invertible and normal composition operators on the Hilbert Hardy space of a half–plane

Operators on function spaces of form Cɸf = f ∘ ɸ, where ɸ is a fixed map are called composition operators with symbol ɸ. We study such operators acting on the Hilbert Hardy space over the right half-plane and characterize the situations when they are invertible, Fredholm, unitary, and Hermitian. We...

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Main Author: Matache Valentin
Format: Article
Language:English
Published: De Gruyter 2016-05-01
Series:Concrete Operators
Subjects:
Online Access:http://www.degruyter.com/view/j/conop.2016.3.issue-1/conop-2016-0009/conop-2016-0009.xml?format=INT
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author Matache Valentin
author_facet Matache Valentin
author_sort Matache Valentin
collection DOAJ
description Operators on function spaces of form Cɸf = f ∘ ɸ, where ɸ is a fixed map are called composition operators with symbol ɸ. We study such operators acting on the Hilbert Hardy space over the right half-plane and characterize the situations when they are invertible, Fredholm, unitary, and Hermitian. We determine the normal composition operators with inner, respectively with Möbius symbol. In select cases, we calculate their spectra, essential spectra, and numerical ranges.
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spelling doaj.art-292bce9640d54c0dab9adf8b9347cfa22022-12-22T00:44:27ZengDe GruyterConcrete Operators2299-32822016-05-0131778410.1515/conop-2016-0009conop-2016-0009Invertible and normal composition operators on the Hilbert Hardy space of a half–planeMatache Valentin0Department of Mathematics, University of Nebraska, Omaha, NE 68182, USAOperators on function spaces of form Cɸf = f ∘ ɸ, where ɸ is a fixed map are called composition operators with symbol ɸ. We study such operators acting on the Hilbert Hardy space over the right half-plane and characterize the situations when they are invertible, Fredholm, unitary, and Hermitian. We determine the normal composition operators with inner, respectively with Möbius symbol. In select cases, we calculate their spectra, essential spectra, and numerical ranges.http://www.degruyter.com/view/j/conop.2016.3.issue-1/conop-2016-0009/conop-2016-0009.xml?format=INTComposition operator Hardy space Half–plane
spellingShingle Matache Valentin
Invertible and normal composition operators on the Hilbert Hardy space of a half–plane
Concrete Operators
Composition operator
Hardy space
Half–plane
title Invertible and normal composition operators on the Hilbert Hardy space of a half–plane
title_full Invertible and normal composition operators on the Hilbert Hardy space of a half–plane
title_fullStr Invertible and normal composition operators on the Hilbert Hardy space of a half–plane
title_full_unstemmed Invertible and normal composition operators on the Hilbert Hardy space of a half–plane
title_short Invertible and normal composition operators on the Hilbert Hardy space of a half–plane
title_sort invertible and normal composition operators on the hilbert hardy space of a half plane
topic Composition operator
Hardy space
Half–plane
url http://www.degruyter.com/view/j/conop.2016.3.issue-1/conop-2016-0009/conop-2016-0009.xml?format=INT
work_keys_str_mv AT matachevalentin invertibleandnormalcompositionoperatorsonthehilberthardyspaceofahalfplane