Three topological problems about integral functionals on Sobolev spaces
  In this paper, I propose some problems, of topological nature, on the energy functional associated to the Dirichlet problem -\Delta u = f(x,u) in Omega, u restricted to the boundary of Omega is 0. Positive answers to these problems would produce innovative multiplicity results on this Dirichlet problem. 
Biagio Ricceri