2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/93432We propose an interpretation of quantum separability based on a physical principle: local time reversal. It immediately leads to a simple characterization of separable quantum states that reproduces results known to hold for binary composite systems and which thereby is complete for low dimensions. We then describe a constructive algorithm for finding the canonical decomposition of separable and non separable mixed states of dimensions 2x2 and 2x3.9 pages, Revtex, no figuresQuantum Physicstext