2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/106234The main result is that the Jacobian determinant of an analytic open map from Euclidean n-space to itself does not change sign. A corollary of the proof is that the set of branch points has dimension < n-1.4 pagesClassical Analysis and ODEs26E05, 26B10 (primary) 54C10 (secondary)text