Multiplicity of bifurcation points for variational inequalities via Conley index (Q1270578)

The paper deals with the study of a nonlinear eigenvalue problem on a closed convex set. The author establishes sufficient conditions for the existence of at least two eigenvalues at which bifurcation occurs. The proofs use elements of nonsmooth critical point theory and it is pointed out that the bifurcation is related to the continuation property of the Conley index. The abstract results are applied to a problem of eigenvalues for a semilinear elliptic variational inequality.