2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/171935The theory of superposition rules for solutions of a Lie system of first-order differential equations is extended to deal with analogous systems of second-order and the theory is illustrated with the very rich example of Ermakov-like systems.18 pagesMathematical Physics34A26, 34A05text