Soul theorem
History
The soul theorem was proved by Cheeger and Gromoll in their paper On the structure of complete manifolds of nonnegative curvature.
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
- On the structure of complete manifolds of nonnegative curvature by Jeff Cheeger and Detlef Gromoll, The Annals of Mathematics, 2nd Ser., Vol. 96, No. 3 (Nov., 1972), pp. 413-443
- 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