Eigenvalues for the Steklov problem via Ljusternic–Schnirelman principle

This paper deals with the existence of nondecreasing sequence of nonnegative eigenvalues for the systemsdiv(a(x)|∇u|p-2∇u)=b(x)|u|p-2uinΩ,|∇u|p-2∂u∂n=λc(x)|u|p-2uon∂Ω,by using the Ljusternic–Schnirelman principle, where Ω is a bounded domain in RN(N ⩾ 2).