| Abstract: | We develop a symplectic method of finding the adiabatic invariants of nonlinear dynamic systems with small parameter. We show that a necessary and sufficient condition for the existence of quasi-Hamiltonian adiabatic invariants of nonlinear dynamic systems with regular dependence on a small parameter is that the Cauchy problem be well-posed for an equation of Lax type in the class of nongradient local functionals on the cotangent manifold of the phase space. It is established that scalar nonlinear dynamic systems always have a priori complete evolution invariants, not only adiabatic invariants. We also consider typical applications in hydrodynamics and oscillatory systems of mathematical physics.Translated fromMatematicheskie Metody i Fiziko-Mekhanicheskie Polya, Issue 35, 1992, pp. 179–185. |
