On compactness theorems for logarithmic interpolation methods

Let (A0;A1) be a Banach couple, (B0;B1) a quasi-Banach couple, 0 < q <= ∞ and T a linear operator. We prove that if T : A0 -> B0 is bounded and T : A1 -> B1 is compact, then the interpolated operator by the logarithmic method T : (A0,A1)1;q;A -> (B0;B1)1;q;A is compact too. This resul...

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Detalhes bibliográficos
Autor: Besoy, Blanca F.
Tipo de documento: artigo
Data de publicação:2019
País:España
Recursos:Universidad Complutense de Madrid (UCM)
Repositório:Docta Complutense
Idioma:inglês
OAI Identifier:oai:docta.ucm.es:20.500.14352/13541
Acesso em linha:https://hdl.handle.net/20.500.14352/13541
Access Level:Acceso aberto
Palavra-chave:517.98
Logarithmic interpolation methods
compact operators
Lorentz-Zygmund spaces.
Análisis funcional y teoría de operadores
Descrição
Resumo:Let (A0;A1) be a Banach couple, (B0;B1) a quasi-Banach couple, 0 < q <= ∞ and T a linear operator. We prove that if T : A0 -> B0 is bounded and T : A1 -> B1 is compact, then the interpolated operator by the logarithmic method T : (A0,A1)1;q;A -> (B0;B1)1;q;A is compact too. This result allows the extension of some limit variants of Krasnosel'skii's compact interpolation theorem.