Naber, AaronValtorta, Daniele2014-08-292014-08-292014-08-29201410.1007/s00209-014-1282-xhttps://infoscience.epfl.ch/handle/20.500.14299/106246WOS:000339343900014We complete the picture of sharp eigenvalue estimates for the -Laplacian on a compact manifold by providing sharp estimates on the first nonzero eigenvalue of the nonlinear operator when the Ricci curvature is bounded from below by a negative constant. We assume that the boundary of the manifold is convex, and put Neumann boundary conditions on it. The proof is based on a refined gradient comparison technique and a careful analysis of the underlying model spaces.text::journal::journal article::research article