Three solutions for a class of Neumann boundary value systems driven by a (p_1,...,p_n)-Laplacian operator

In this paper, we prove the existence of at least three weak solutions for Neumann doubly eigenvalue elliptic systems involving the (p_1, . . . , p_n )-Laplacian. The approach is based on a recent three critical points theorem obtained by B. Ricceri [9]. We also give some examples to illustrate the obtained results.