2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/33524It is standard assertion in relativity that, subject to an energy condition and the cosmic censorship hypothesis, closed trapped surfaces are not visible from future null infinity. A proof given by Hawking & Ellis in ''The Large Scale Structure of Space-Time'' is flawed since it is formulated in terms of an inadequate definition of a weakly asymptotically simple and empty space-time. A new proof is given based on a more restrictive definition of a weakly asymptotically simple and empty space-time.15 pages, 4 figures. Uses the following packages: amsmath,amsthm, amssymb, amsfonts, mathrsfs, enumerate, graphicxGeneral Relativity and Quantum Cosmologytext