RIGIDITY OF CLOSED METRIC MEASURE SPACES WITH NONNEGATIVE CURVATURE

摘要

We show that one-dimensional circle is the only case for closed smooth metric measure spaces with nonnegative Bakry-Emery Ricci curvature whose spectrum of the weighted Laplacian has an optimal positive upper bound. This result extends the work of Hang-Wang in the manifold case (Int. Math. Res. Not. 18 (2007), Art. ID rnm064, 9pp).