2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/91083The additivity of both the entanglement of formation and the classical channel capacity is known to be a consequence of the strong superadditivity conjecture. We show that, conversely, the strong superadditivity conjecture follows from the additivity of the entanglement of formation; this means that the two conjectures are equivalent and that the additivity of the classical channel capacity is a consequence of them.revtex, 7 pages, research at Quantware MIPS Center http://www.quantware.ups-tlse.frQuantum Physicstext