Το work with title A multiplicity result for quasilinear problems with convex andconcave nonlinearities and nonlinear boundary conditions in unbounded domains by Kandylakis Dimitrios is licensed under Creative Commons Attribution 4.0 International
Bibliographic Citation
D.A. Kandilakis, "A multiplicity result for quasilinear problems with convex and
concave nonlinearities and nonlinear boundary conditions in unbounded domain,"Electronic Journal of Differential Equations, vol. 2005, no. 57, pp. 1–12, 2005.
We study the following quasilinear problem with nonlinear boundaryconditions−∆pu = λa(x)|u|p−2u + k(x)|u|q−2u − h(x)|u|s−2u, in Ω,|∇u|p−2∇u · η + b(x)|u|p−2u = 0 on ∂Ω,where Ω is an unbounded domain in RN with a noncompact and smoothboundary ∂Ω, η denotes the unit outward normal vector on ∂Ω, ∆pu =div(|∇u|p−2∇u) is the p-Laplacian, a, k, h and b are nonnegative essentiallybounded functions, q < p < s and p∗ < s. The properties of the first eigenvalueλ1 and the associated eigenvectors of the related eigenvalue problem areexamined. Then it is shown that if λ < λ1, the original problem admits an infi-nite number of solutions one of which is nonnegative, while if λ = λ1 it admitsat least one nonnegative solution. Our approach is variational in character