An extremal composition operator on the Hardy space of the bidisk with small approximation numbers

We construct an analytic self-map φ of the bidisk D2 whose image touches the distinguished boundary, but whose approximation numbers of the associated composition operator on H2(D2) are small in the sense that lim sup n-->[an2 (Cφ)]1/n<1.

Detalles Bibliográficos
Autores: Li, Daniel, Queffélec, Hervé, Rodríguez Piazza, Luis
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2020
País:España
Institución:Universidad de Sevilla (US)
Repositorio:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/182774
Acceso en línea:https://hdl.handle.net/11441/182774
https://doi.org/10.1016/j.jat.2019.105363
Access Level:acceso abierto
Palabra clave:Approximation numbers
Bidisk
Composition operator
Cusp map
Distinguished boundary
Hardy space
Descripción
Sumario:We construct an analytic self-map φ of the bidisk D2 whose image touches the distinguished boundary, but whose approximation numbers of the associated composition operator on H2(D2) are small in the sense that lim sup n-->[an2 (Cφ)]1/n<1.