2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/64747We prove that the stable endomorphism algebra of a module without self-extensions over a special biserial algebra is a gentle algebra. In particular, it is again special biserial. As a consequence, any algebra which is derived equivalent to a gentle algebra is gentle.Representation Theory16E30, 16G20, 18E30text