Some Remarks on the Fucik Spectrum of the p-Laplacian and Critical   Groups
  We compute critical groups of variational functionals arising from quasilinear elliptic boundary value problems with jumping nonlinearities, when the asymptotic limits of the equation lie in various regions of the plane that are separated by certain curves of the Fucik spectrum. As an application some existence and multiplicity results are established via Morse theoretic and perturbation arguments. 
Norman Dancer (1), Kanishka Perera (2) ((1) University of Sydney, NSW,   Australia, (2) Florida Institute of Technology, Mel...