On existence and multiplicity of solutions of Neumann boundary value problems for quasi-linear elliptic equations

In the present paper, the following Neumann boundary value problem involving the pp-Laplacian equation(1.1){−Δp(u)=f(x,u),inΩ∂u∂n=0,on∂Ω is studied and some new existence and multiplicity results of solutions for the problem (1.1) are obtained.