Soul theorem Guide, Meaning , Facts, Information and Description
In mathematics, the soul theorem is a classical theorem of Riemannian geometry. It can be stated as follows:
If (M,g) is a complete non-compact Riemannian manifold with sectional curvature , then (M,g) has a compact totally convex, totally geodesic submanifold S such that M is diffeomorphic to its normal bundle of N(S).
The submanifold S above is called a soul of (M, g); it is not uniquely determined, but any two souls are isometric.
The theorem was proved by Jeff Cheeger and Detlef Gromoll, as a generalization of an earlier result of Gromoll and Wolfgang Meyer.
In the same paper Cheeger and Gromoll gave the following conjecture:
The conjecture was open for about 20 years, and was solved by Grigori Perelman with a surprisingly short argument.Soul conjecture
Suppose, M is complete and noncompact with sectional curvature , but at some point. Then soul of M has to be a point (or equivalently M is diffeomorphic to ).
