Abstract:
According to Moser, the study of normal forms in dynamical systems should be expressed in terms of infinite dimensional group actions. I present a functional analytic setting and an abstract version of the KAM theorem as a new starting point to develop this program.
Key words and phrases:
KAM theory, perturbation theory, Herman conjecture.
Received:April 10, 2013; in revised form March 31, 2014