2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/139039We want to give a construction as simple as possible of a Borel subset of a product of two Polish spaces. This introduces the notion of potential Wadge class. Among other things, we study the non-potentially closed sets, by proving Hurewicz-like results. This leads to partial uniformization theorems, on big sets, in the sense of cardinality or Baire category.LogicGeneral Topology03E15, 54H05text