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
- 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