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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Bibliographic Details
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
Description
Summary: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.
ISSN:2299-3282