Compact composition operators on the Dirichlet space and capacity of sets of contact points

We prove several results about composition operators on the Dirichlet space D⁎. For every compact set K⊆∂D of logarithmic capacity , there exists a Schur function φ both in the disk algebra A(D) and in D⁎ such that the composition operator Cφ is in all Schatten classes Sp(D⁎), p>0, and for which...

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Bibliographic Details
Authors: Lefèvre, Pascal, Li, Daniel, Queffélec, Hervé, Rodríguez Piazza, Luis
Format: article
Status:Versión enviada para evaluación y publicación
Publication Date:2013
Country:España
Institution:Universidad de Sevilla (US)
Repository:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/46350
Online Access:http://hdl.handle.net/11441/46350
https://doi.org/10.1016/j.jfa.2012.12.004
Access Level:Open access
Keyword:Bergman space
Bergman-Orlicz space
Composition operator
Dirichlet space
Hardy space
Hardy-Orlicz space
Logarithmic capacity
Schatten classes
Description
Summary:We prove several results about composition operators on the Dirichlet space D⁎. For every compact set K⊆∂D of logarithmic capacity , there exists a Schur function φ both in the disk algebra A(D) and in D⁎ such that the composition operator Cφ is in all Schatten classes Sp(D⁎), p>0, and for which . For every bounded composition operator Cφ on D⁎ and every ξ∈∂D, the logarithmic capacity of is 0. Every compact composition operator Cφ on D⁎ is compact on BΨ2 and on HΨ2; in particular, Cφ is in every Schatten class Sp, p>0, both on H2 and on B2. There exists a Schur function φ such that Cφ is compact on HΨ2, but which is not even bounded on D⁎. There exists a Schur function φ such that Cφ is compact on D⁎, but in no Schatten class Sp(D⁎).