2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/116690A permutation class which is closed under pattern involvement may be described in terms of its basis. The wreath product construction X \wr Y of two permutation classes X and Y is also closed, and we investigate classes Y with the property that, for any finitely based class X, the wreath product X \wr Y is also finitely based.14 pagesCombinatorics05A05text