• Invariant Tori in Hamiltonian Systems with High Order Proper Degeneracy 

      Han, Yuecai; Li, Yong; Yi, Yingfei (Georgia Institute of Technology, 2009)
      We study the existence of quasi-periodic, invariant tori in a nearly integrable Hamiltonian system of high order proper degeneracy, i.e., the integrable part of the Hamiltonian involves several time scales and at each time ...