A Weighted Discretization of Riemannian Manifolds with Lower Ricci Bounds

Abstract

Let $(M,g)$ be a connected, compact, $n$-dimensional Riemannian manifold with $\mathrm{Ric}(M,g)\ge -(n-1)\kappa g$. We introduce a weighted combinatorial Laplacian on $\epsilon$-discretizations of $M$ and prove a spectral comparison theorem between the weighted graph Laplacian and the Laplace-Beltrami operator. More precisely, the eigenvalues of the two operators are uniformly comparable with constants depending only on $n,\kappa ,\epsilon$, independently of the injectivity radius. As an application, we prove spectral stability under measured Gromov-Hausdorff convergence. We also recover the Schoen-Wolpert-Yau inequality using the weighted discretization on families of pinching genus-$2$ hyperbolic surfaces.

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