2010/01/14 by Samuel Tapie, Tapie, Samuel
Mathematics · #53C21 #58C40 #Differential Geometry (math.DG) #FOS: Mathematics #Geometric Analysis and Curvature Flows #Geometric and Algebraic Topology #Nonlinear Partial Differential Equations #Spectral Theory (math.SP)
paper · pdf · doi:10.48550/arxiv.1001.2506
openalex publication_date 2010/01/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Let (M,g) be a non-compact riemannian n-manifold with bounded geometry at order k≥(n)/(2). We show that if the spectrum of the Laplacian starts with q+1 discrete eigenvalues isolated from the essential spectrum, and if the metric is generic for the \Cl Ck+2-strong topology, then the eigenvalues are distinct and their associated eigenfunctions are Morse. This generalizes to non-compact manifolds some arguments developped by K. Uhlenbeck. We deduce from this result that if Mn has bounded geometry at order k≥(n)/(2) and has an isolated first eigenvalue for its Laplacian, then for any riemannian covering p : M'\ra M, we have λ0(M) = supD λ0(D), where D⊂ M' runs over all connected fundamental domains for p, and λ0(D) is the bottom of the spectrum of D with Neumann boundary conditions.