Linear and nonlinear eigenvalue problems for Dirac systems in unbounded domains

We first study the linear eigenvalue problem for a planar Dirac system in the open half-line and describe the nodal properties of its solutions by means of the rotation number. We then give a global bifurcation result for a planar nonlinear Dirac system in the open half-line. As an application, we provide a global continuum of solutions of the nonlinear Dirac equation which have a special form

A Multiplicity result for a class of strongly indefinite asymptotically linear second order systems

We prove a multiplicity result for a class of strongly indefinite nonlinear second order asymptotically linear systems with Dirichlet boundary conditions. The key idea for the proof is to bring together the classical shooting method and the Maslov index of the linear Hamiltonian systems associated to the asymptotic limits of the given nonlinearity.Comment: 19 pages. No figure