Editing Kolmogorov–Arnold–Moser theorem (section)

===Integrable Hamiltonian systems===

The KAM theorem is usually stated in terms of trajectories in [[phase space]] of an integrable [[Hamiltonian system]]. The motion of an [[integrable system]] is confined to an [[invariant torus]] (a [[doughnut]]-shaped surface).  Different [[initial condition]]s of the integrable Hamiltonian system will trace different invariant [[torus|tori]] in phase space.  Plotting the coordinates of an integrable system would show that they are quasiperiodic.