2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/179398We revisit the decoupling phenomenon of massless modes in the noncommutative open string (NCOS) theories. We check the decoupling by explicit computation in (2+1) or higher dimensional NCOS theories and recapitulate the validity of the decoupling to all orders in perturbation theory.12 pages, latex2e, 2 figures; reference added, some modification without changing resultHigh Energy Physics - Theorytext