Approximation numbers of weighted composition operators

We study the approximation numbers of weighted composition operators f 7→ w · (f ◦ ϕ) on the Hardy space H2 on the unit disc. For general classes of such operators, upper and lower bounds on their approximation numbers are derived. For the special class of weighted lens map composition operators wit...

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Detalles Bibliográficos
Autores: Lechner, Gandalf, Li, Daniel, Queffélec, Hervé, Rodríguez Piazza, Luis
Tipo de recurso: artículo
Estado:Versión enviada para evaluación y publicación
Fecha de publicación:2018
País:España
Institución:Universidad de Sevilla (US)
Repositorio:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/69957
Acceso en línea:https://hdl.handle.net/11441/69957
https://doi.org/10.1016/j.jfa.2018.01.010
Access Level:acceso abierto
Palabra clave:Composition operators
Approximation numbers
von Neumann algebras
Descripción
Sumario:We study the approximation numbers of weighted composition operators f 7→ w · (f ◦ ϕ) on the Hardy space H2 on the unit disc. For general classes of such operators, upper and lower bounds on their approximation numbers are derived. For the special class of weighted lens map composition operators with specific weights, we show how much the weight w can improve the decay rate of the approximation numbers, and give sharp upper and lower bounds. These examples are motivated from applications to the analysis of relative commutants of special inclusions of von Neumann algebras appearing in quantum field theory (Borchers triples).