Multiple Periodic Solutions for an Asymptotically Linear Wave Equation.
Kai‐Wei Chang, S. P. Wu, Shujie Li · 1981
Two kinds of existence of multiple periodic solutions for an asymptotically linear wave equation are studied. The first concerns the existence of at least three distinct solutions without any group symmetry assumptions on the nonlinear term. The second deals with an estimation of the number of solutions based on the asymptotic behaviour of the nonlinear term at zero and at infinity under an oddness assumption. (Author)