2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/28041The nonadiabatic effects due to the breakdown of Migdal's theorem in high-$T_c$ superconductors are strongly affected by the opening of the superconducting gap. Here we report how the momentum-frequency dependence of vertex corrections is modified by the gap. A general effect is that the positive region of the vertex corrections is increased leading to an enhancement of their relevance. This has a number of physical consequences that we discuss in details in relation to specific experiments.6 pages RevTeX, 6 eps figuesSuperconductivitytext