Inscribed and circumscribed radius of $\kappa$-convex hypersurfaces in Hadamard manifolds

Abstract

Let $P$ be a convex polygon in a Hadamard surface $M$ with curvature $K$ satisfying $-k_2^2\ge K\ge -k_1^2$. We give an upper bound of the circumradius of $P$ in terms of a lower bound of the curvature of $P$ at its vertices.