Splitting theorem: Difference between revisions
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==Statement== | ==Statement== | ||
Any [[geodesically complete Riemannian manifold|complete]] Riemannian manifold whose [[Ricci curvature]] is everywhere nonnegative can be expressed as a direct product of a [[ | Any [[geodesically complete Riemannian manifold|complete]] Riemannian manifold whose [[Ricci curvature]] is everywhere nonnegative can be expressed as a direct product of a [[Euclidean space]] and a Riemannian manifold which does not contain any [[line]]. (A line here is a geodesic every finite segment of which realizes the distance between its endpoints). | ||
==Relation with other results== | ==Relation with other results== | ||
Revision as of 12:31, 5 August 2007
This article describes a result related to the Ricci curvature of a Riemannian manifold
Statement
Any complete Riemannian manifold whose Ricci curvature is everywhere nonnegative can be expressed as a direct product of a Euclidean space and a Riemannian manifold which does not contain any line. (A line here is a geodesic every finite segment of which realizes the distance between its endpoints).
Relation with other results
Bonnet-Myers theorem
Further information: Bonnet-Myers theorem
The Bonnet-Myers theorem states a very similar result for a manifold which has positive Ricci curvature everywhere, bounded below by a positive constant. Note that the Bonnet-Myers theorem, which asserts that any such manifold is compact, implies that it does not contain any line. Thus, the splitting theorem is closely related to the Bonnet-Myers theorem, the difference being that it allows zero curvature.