2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/60275We consider the problem of Arnold's diffusion for nearly integrable isochronous Hamiltonian systems. We prove a shadowing theorem which improves the known estimates for the diffusion time. We also develop a new method for measuring the splitting of the separatrices. As an application we justify, for three time scales systems, that the splitting is correctly predicted by the Poincaré-Melnikov function.32 pagesDynamical SystemsSymplectic Geometrytext