We study the bifurcation and the exact multiplicity of solutions for a class of Neumann ECHINAFORCE boundary value problem with indefinite weight.We prove that all the solutions obtained form a smooth reversed S-shaped curve by topological degree theory, Crandall-Rabinowitz bifurcation theorem, and the uniform antimaximum principle in terms of eigenvalues.Moreover, we obtain that the equation has exactly either one, two, or three solutions depending on the real parameter.
The CINNAMAX stability is obtained by the eigenvalue comparison principle.