Multiple solutions to a perturbed Neumann problem

Giuseppe Cordaro

Studia Mathematica, Tome 178 (2007), p. 167-175 / Harvested from The Polish Digital Mathematics Library

Résumé

We consider the perturbed Neumann problem ⎧ -Δu + α(x)u = α(x)f(u) + λg(x,u) a.e. in Ω, ⎨ ⎩ ∂u/∂ν = 0 on ∂Ω, where Ω is an open bounded set in $ℝ^{N}$ with boundary of class C², $α ∈ L^{∞}(Ω)$ with $ess inf_{Ω}α > 0$, f: ℝ → ℝ is a continuous function and g: Ω × ℝ → ℝ, besides being a Carathéodory function, is such that, for some p > N, $sup_{|s|≤t} |g(⋅,s)| ∈ L^{p}(Ω)$ and $g(⋅,t) ∈ L^{∞}(Ω)$ for all t ∈ ℝ. In this setting, supposing only that the set of global minima of the function $1/2 ξ² - ∫_{0}^{ξ} f(t)dt$ has M ≥ 2 bounded connected components, we prove that, for all λ ∈ ℝ small enough, the above Neumann problem has at least M+integer part of M/2 distinct strong solutions in $W^{2,p}(Ω)$.

Détail

Publié le : 2007-01-01

Zbl 05115202

EUDML-ID : urn:eudml:doc:284813