First numerical evidence of global Arnold diffusion in quasi--integrable   systems
  We provide numerical evidence of global diffusion occurring in slightly perturbed integrable Hamiltonian systems and symplectic maps. We show that even if a system is sufficiently close to be integrable, global diffusion occurs on a set with peculiar topology, the so--called Arnold web, and is qualitatively different from Chirikov diffusion, occurring in more perturbed systems. 
Massimiliano Guzzo (Dipartimento di Matematica Pura ed Applicata,   Universita' degli Studi di Padova, Padova, Italy.) Elena...