COUNTING SOLUTIONS IN BIFURCATION PROBLEMS

摘要

In this paper, we use the topological degree to obtain some sharp lower bounds for the number of solutions of the parameter slices of the semi-bounded components of the set of nontrivial solutions of an abstract nonlinear equation with a trivial state. By a semi-bounded component one means a component that is bounded in one direction of the parameter. The spectrum of linearization of the equation at the trivial state is not assumed to be discrete.