A SADDLE POINT THEOREM FOR NON-SMOOTH FUNCTIONALS AND PROBLEMS AT RESONANCE
Constantin P. Niculescu · 1996
We prove a saddle point theorem for locally Lipschitz functionals with arguments based on a version of the mountain pass theorem for such kind of functionals. This abstract result is applied to solve two different types of multivalued semilinear elliptic boundary value problems with a Laplace-Beltrami operator on a smooth compact Riemannian manifold.