sphere theorem
theorem stating that a complete, simply-connected, n-dimensional Riemannian manifold with sectional curvature taking values in the interval (1, 4] is homeomorphic to the n-sphere
en-GB/sˈfɪə ˈθɪəɹəm/
en-US/ˈsfɪɹ ˈθɪɹəm/
theorem stating that a complete, simply-connected, n-dimensional Riemannian manifold with sectional curvature taking values in the interval (1, 4] is homeomorphic to the n-sphere