Hadamard manifold

Summary

In mathematics, a Hadamard manifold, named after Jacques Hadamard — more often called a Cartan–Hadamard manifold, after Élie Cartan — is a Riemannian manifold that is complete and simply connected and has everywhere non-positive sectional curvature.[1][2] By Cartan–Hadamard theorem all Cartan–Hadamard manifolds are diffeomorphic to the Euclidean space Furthermore it follows from the Hopf–Rinow theorem that every pairs of points in a Cartan–Hadamard manifold may be connected by a unique geodesic segment. Thus Cartan–Hadamard manifolds are some of the closest relatives of

Examples

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The Euclidean space   with its usual metric is a Cartan–Hadamard manifold with constant sectional curvature equal to  

Standard  -dimensional hyperbolic space   is a Cartan–Hadamard manifold with constant sectional curvature equal to  

Properties

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In Cartan-Hadamard manifolds, the map   is a diffeomorphism for all  

See also

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References

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  1. ^ Li, Peter (2012). Geometric Analysis. Cambridge University Press. p. 381. doi:10.1017/CBO9781139105798. ISBN 9781107020641.
  2. ^ Lang, Serge (1989). Fundamentals of Differential Geometry, Volume 160. Springer. pp. 252–253. ISBN 9780387985930.