2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/222290We prove that there exist weakly countably determined spaces of complexity higher than coanalytic. On the other hand, we also show that coanalytic sets can be characterized by the existence of a cofinal adequate family of closed sets. Therefore the Banach spaces constructed by means of these families have at most coanalytic complexity.This version differs from the published in Studia Mathematica in that there is a short correction to a mistake discovered by the MR reviewerFunctional Analysis46B26text