2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/61071We consider the problem of Arnold Diffusion for nearly integrable partially isochronous Hamiltonian systems with three time scales. By means of a careful shadowing analysis, based on a variational technique, we prove that, along special directions, Arnold diffusion takes place with fast (polynomial) speed, even though the ``splitting determinant'' is exponentially small.Dynamical Systems34J40, 37J45text