Recurrent dimensions and extended common multiples of quasi-periodic orbits given by solutions of second order nonlinear evolution equations (Q2520012)

In an earlier work [Discrete Contin. Dyn. Syst. 11, No. 2--3, 449--488 (2004; Zbl 1058.37018)], conditions in terms of `extended common multiples' (ECM) for a pair of irrationals were used to estimate the recurrent dimension of quasi-periodic orbits. Here a quasi-periodic property for functions is defined, and used to study solutions of a second-order nonlinear evolution equation with a quasi-periodic perturbing term; the recurrent dimension of orbits is estimated under an ECM condition.