2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/73541We show a geometric rigidity of isometric actions of non compact (semisimple) Lie groups on Lorentz manifolds. Namely, we show that the manifold has a warped product structure of a Lorentz manifold with constant curvature by a Riemannian manifold.Dynamical SystemsDifferential GeometryMSC : 53A35, 37C85, 57S20text