Some properties and applications of equicompact sets of operators

Let X and Y be Banach spaces. A subset M of K(X,Y ) (the vector space of all compact operators from X into Y endowed with the operator norm) is said to be equicompact if every bounded sequence (xn) in X has a subsequence (xk(n))n such that (Txk(n))n is uniformly convergent for T ∈ M. We study the re...

Descripción completa

Detalles Bibliográficos
Autores: Serrano Aguilar, Enrique, Piñeiro Gómez, Cándido, Delgado Sánchez, Juan Manuel
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2007
País:España
Institución:Universidad de Sevilla (US)
Repositorio:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/96304
Acceso en línea:https://hdl.handle.net/11441/96304
https://doi.org/10.4064/sm181-2-4
Access Level:acceso abierto
Palabra clave:Compact operators
Equicompact sets of operators
Collectively compact set
Vector measures
Ascoli’s theorem
Descripción
Sumario:Let X and Y be Banach spaces. A subset M of K(X,Y ) (the vector space of all compact operators from X into Y endowed with the operator norm) is said to be equicompact if every bounded sequence (xn) in X has a subsequence (xk(n))n such that (Txk(n))n is uniformly convergent for T ∈ M. We study the relationship between this concept and the notion of uniformly completely continuous set and give some applications. Among other results, we obtain a generalization of the classical Ascoli theorem and a compactness criterion in Mc(F,X), the Banach space of all (finitely additive) vector measures (with compact range) from a field F of sets into X endowed with the semivariation norm.