Hadamard manifold

In mathematics, a Hadamard manifold, named after Jacques Hadamard — more often called a Cartan–Hadamard manifold, after Élie Cartan — is a Riemannian manifold (Mg) that is complete and simply connected and has everywhere non-positive sectional curvature.[1][2] By Cartan–Hadamard theorem all Cartan–Hadamard manifold 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 .

ExamplesEdit

  • The Euclidean space Rn with its usual metric is a Cartan-Hadamard manifold with constant sectional curvature equal to 0.
  • Standard n-dimensional hyperbolic space Hn is a Cartan-Hadamard manifold with constant sectional curvature equal to −1.

See alsoEdit

ReferencesEdit

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