The multiplicity of solutions and geometry of a nonlinear elliptic equation
Q-Heung Choi · Studia Mathematica · 1996
Let Ω be a bounded domain in $ℝ^n$ with smooth boundary ∂Ω and let L denote a second order linear elliptic differential operator and a mapping from $L^2(Ω)$ into itself with compact inverse, with eigenvalues $-λ_{i}$, each repeated according to its multip