Subharmonic solutions with prescribed minimal period for nonautonomous Hamiltonian systems (Q1103090)

The authors study the system (*) \(J\dot z=H_ z(z,t)\) where J is the symplectic matrix and \(H(z,t+T)=H(z,t)\), and they seek solutions satisfying \(z(0)=z(pT)\), for any integer \(p>1\). \(H(z,t)\) is assumed to satisfy both convexity and growth conditions in z. Using analytical as well as topological techniques they establish the existence of subharmonic solutions.