Periodic solutions for second order Hamiltonian systems on an arbitrary energy surface
Tom 105 / 2012
Annales Polonici Mathematici 105 (2012), 1-12 MSC: Primary 34C25; Secondary 58E05. DOI: 10.4064/ap105-1-1
Two theorems about the existence of periodic solutions with prescribed energy for second order Hamiltonian systems are obtained. One gives existence for almost all energies under very natural conditions. The other yields existence for all energies under a further condition.