  We prove the existence of "Arnold diffusion orbits" in cusp-generic nearly
integrable a priori stable systems on ${\mathbb A}^3$. The result relies on the
cusp-generic existence of chains in nearly integrable a priori stable systems,
proved in a previous paper, together with the existence of diffusion orbits
along such chains. The latter result was obtained in collaboration with M.
Gidea.
