This paper investigates the question of stability for a class of Ricci flows which start at possibly non-smooth metric spaces. We show that if the initial metric space is Reifenberg and locally bi-Lipschitz to Euclidean space, then two solutions to the Ricci flow whose Ricci curvature is uniformly bounded from below and whose curvature is bounded by c • t −1 converge to one another at an exponential rate once they have been appropriately gauged. As an application, we show that smooth three dimensional, complete, uniformly Ricci-pinched Riemannian manifolds with bounded curvature are either compact or flat, thus confirming a conjecture of Hamilton and Lott.
Contents1. Introduction 1.1. Overview 1.2. Outline of paper 1.3. Notation 1.4. Acknowldgements 2. Curvature decay 3. Existence of an adjustment map 4. Rough convergence rate 5. Polynomial convergence rate 6. Exponential convergence rate 7. Almost Ricci-pinched expanding gradient Ricci solitons 8. Compactness of Ricci-pinched manifolds in dimension three Appendix A. Volume and distance convergence, for solutions to Ricci flow with Ric ≥ −1 and curvature bounded by c 0 /t Appendix B. A splitting theorem of R. Hochard for the Ricci flow in a singular setting References