2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/150177We give a condition for certain divisors on the blow up of P^3 at points in general position to be ample. The result extends a theorem of G. Xu on the blow up of the projective plane.AMS-LaTeX, 9 pagesAlgebraic Geometrytext