2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/152759It is proved that if a Banach space $Y$ is a quotient of a Banach space having a shrinking unconditional basis, then every normalized weakly null sequence in $Y$ has an unconditional subsequence. The proof yields the corollary that every quotient of Schreier's space is $c_o$-saturated.Functional Analysis46Btext