MATHEMATICAL PROBLEMS OF NONLINEARITYMathematical Problems of Nonlinearity • March 31st, 2021
Remark 3. It is worth noting that using the sets of symplectic coordinates (2.7) and (2.8), we can parameterize each periodic solution of the Hamiltonian (2.2) in terms of the angle l = l(t). More precisely, if pj(t, ε) = (x1(t, ε), x2(t, ε), y1(t, ε), y2(t, ε)) is the periodic solution associated to the critical point Oj, then
