2021/03/25 by de la Llave, Rafael, Saprykina, Maria · 1 citation
#Dynamical Systems (math.DS) #FOS: Mathematics
paper · doi:10.48550/arxiv.2103.13535
Consider an analytic Hamiltonian system near its analytic invariant torus \mathcal T0 carrying zero frequency. We assume that the Birkhoff normal form of the Hamiltonian at \mathcal T0 is convergent and has a particular form: it is an analytic function of its non-degenerate quadratic part. We prove that in this case there is an analytic canonical transformation -- not just a formal power series -- bringing the Hamiltonian into its Birkhoff normal form.