Problemas de auto- valor não- lineares: métodos topológicos, variacionais e um teorema geral de sub e super soluções

Abstract

In this work we study existence and multiplicity of non-negative solutions of the nonlinear elliptic problem −div(A(x,∇u)) = λf(x,u) in Ω, u = 0 in ∂Ω where Ω⊂IRN is a bounded domain with smooth boundary∂Ω,λ≥ 0 is a parameter, f :Ω×[0,∞)−→ IR and A :Ω×IRN−→ IRN satisfy the Carathéodory conditions, A is monotone and f satisfies a growth condition. To this end we use the method of Sub and Supersolutions, Topological Degree Theory, simmetry arguments and variational methods.