2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/153709We show that for $q\not=-1$ the q-graded tensor product fails to preserve the q-differential structure of the product algebra and therefore there is no natural tensor product construction for q-differential algebras.LaTeX, 10 pagesQuantum Algebra46L87, 81R50text