Answers are grounded in this paper and cite their sources.
We show that if a complete Riemannian manifold supports a vector field such that the Ricci tensor plus the Lie derivative of the metric with respect to the vector field has a positive lower bound, then the fundamental group is finite. In particular, it follows that complete shrinking Ricci solitons and complete smooth metric measure spaces with a positive lower bound on the Bakry-Emery tensor have finite fundamental group. The method of proof is to generalize arguments of García-Río and Fernández-López in the compact case.
No takes yet. Share an insight, caveat, or question.
William Wylie (2007) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: