2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/121554We consider this and related questions: When is a finite linear combination of composition operators, acting on the Hardy space or the standard weighted Bergman spaces on the unit disk, a compact operator?36 pages; to appear in Transactions of the Amer. Math. SocFunctional Analysis47B33text