Locally nearly spherical surfaces are almost-positively -curved
arXiv:1009.3586
Abstract
The -curvature of a complete surface with Gauss curvature close to 1 in norm is almost-positive (in the sense of Kim--McCann). Our proof goes by a careful case by case analysis combined with perturbation arguments from the constant curvature case, keeping track of an estimate on the closeness curvature condition.