RT Journal Article T1 Best possible Compactness Results of Lions-Peetre Type A1 Cobos Díaz, Fernando A1 Cwikel, M. A1 Matos, P. AB If T : A0 ! B boundedly and T : A1 ! B compactly, then a result of Lions{Peetre shows that T : A ! B compactly for a certain class of spaces A which are intermediate with respect to A0 and A1. We investigate to what extent such results can hold for arbitrary intermediate spaces A. The `dual' case of an operator S such that S : X ! Y0 boundedly and S : X ! Y1 compactly, is also considered,as well as similar questions for other closed operator ideals. PB Cambridge Univ Press SN 0013-0915 YR 2001 FD 2001 LK https://hdl.handle.net/20.500.14352/57226 UL https://hdl.handle.net/20.500.14352/57226 LA eng NO Dirección General de Enseñanza Superior (España) NO Fund for Promotion of Research at the Technion NO Progama Praxos XXI da Fundaçao para a Ciencia e Tecnologia NO Instituto Politécnico de Leiria DS Docta Complutense RD 7 abr 2025