2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/201075We study manifolds with Lorentzian signature and prove that all scalar curvature invariants of all orders vanish in a higher-dimensional Lorentzian spacetime if and only if there exists an aligned non-expanding, non-twisting, geodesic null direction along which the Riemann tensor has negative boost order.final versionGeneral Relativity and Quantum CosmologyHigh Energy Physics - Theorytext