Periodic solution of second-order Hamiltonian systems with a change sign potential on time scales (Q1040119)

Summary: This paper is concerned with the second-order Hamiltonian system on time scales \(\mathbb T\) of the form \[ u^\Delta\Delta(\rho(t))+\mu b(t)|u(t)|\mu-2u(t)+\overline\nabla H(t,u(t))=0,\quad \Delta\text{-a.e. }t\in [0,T]_{\mathbb T}, \] \[ u(0)-u(T)=u\Delta (\rho(0))-u\Delta(\rho(T))=0, \] where \(0,T\in\mathbb T\). By using the minimax methods in critical theory, an existence theorem of periodic solution for the above system is established. As an application, an example is given to illustrate the result. This is probably the first time the existence of periodic solutions for second-order Hamiltonian system on time scales has been studied by critical theory.