Martín Peinador, Elena2023-06-212023-06-211985https://hdl.handle.net/20.500.14352/65462X Jornadas Hispano-Lusas de Matemáticas, 21-25 de enero de 1985, Murcia, España.Let B and X be Banach spaces, let B be reflexive, and let (an) be a sequence in B. The author shows that inf{∑|fan|:f∈B*,||f||=1}>0 if and only if the subspace {f∈B*:∑|fan|<∞} contains no closed infinite-dimensional subspace of B*, and in that case we have, for any bounded operator T:B→X,(i)T* is strictly singular whenever ∑Tan is weakly unconditionally Cauchy, and (ii) T is compact whenever ∑||Tan||<∞.book parthttp://cisne.sim.ucm.es/record=b2196627~S6*spihttp://cisne.sim.ucm.esmetadata only access515.1517517.98Análisis matemáticoTopología1202 Análisis y Análisis Funcional1210 Topología