Existence and continuation of solutions for a nonlinear Neumann problem

Abstract

In this article we study the existence, continuation and bifurcation from infinity of nonconstant solutions for a nonlinear Neumann problem. We apply the Leray-Schauder degree and the degree for S O (2)-equivariant gradient operators defined by the second author in [S. Rybicki, S O (2)-degree for orthogonal maps and its applications to bifurcation theory, Nonlinear Anal. TMA 23 (1) (1994) 83-102]. © 2007 Elsevier Ltd. All rights reserved.