The Nehari manifold for a semilinear elliptic equation with a sign-changing weight function

AbstractThe Nehari manifold for the equation −Δu(x)=λa(x)u(x)+b(x)|u(x)|ν−1u(x) for x∈Ω together with Dirichlet boundary conditions is investigated. Exploiting the relationship between the Nehari manifold and fibrering maps (i.e., maps of the form t→J(tu) where J is the Euler functional associated with the equation) we discuss how the Nehari manifold changes as λ changes and show how existence and non-existence results for positive solutions of the equation are linked to properties of the manifold