Sharp Entropy Bounds for Self-Shrinkers in Mean Curvature Flow

Abstract

Let $M\subset {\mathbf R}^{m+1}$ be a smooth, closed, codimension-one self-shrinker (for mean curvature flow) with nontrivial $k^{\rm th}$ homology. We show that the entropy of $M$ is greater than or equal to the entropy of a round $k$-sphere, and that if equality holds, then $M$ is a round $k$-sphere in ${\mathbf R}^{k+1}$.Comment: 7 pages. The new version (Oct 13, 2018) incorporates a few changes and clarifications suggested by the Geometry and Topology referee