2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/100482Contrary to the customary thought prevailing for long, the time reversibility associated with beam-to-beam collisions does not really exist. Related facts and consequences are presented. The discussion, though involving simple mathematics and physics only, is well-related to the foundation of statistical theory.10 pages, 5 figures, latexStatistical Mechanicstext