Soul theorem
Statement
Any open Riemannian manifold with nonnegative sectional curvature contains a compact totally geodesic submanifold (called the soul), such that is diffeomorphic to the normal bundle on , viz .
References
- Improving the metric in an open manifold with nonnegative curvature by Luis Guijarro, Proceedings of the American Mathematical Society, Volume 126, Number 5, May 1998, Pages 1541-1545