2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/70478We have one more look at the (homological) perturbation lemma and we point out some non-standard consequences, including the relevance to deformations.13 pagesAlgebraic TopologyDifferential GeometrySymplectic GeometryOn the perturbation lemma, and deformationstext