2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/66337We extend the method of minimal vectors to arbitrary Banach spaces. It is proved, by a variant of the method, that certain quasinilpotent operators on arbitrary Banach spaces have hyperinvariant subspaces.6 pages. To appear in Proc. Amer. Math. SocFunctional Analysistext