Approximating maps into manifolds with lower curvature bounds
摘要
Many interesting functions arising in applications map into Riemannian manifolds. We present an algorithm, using the manifold exponential and logarithm, for approximating such functions. Our approach uses techniques to approximate functions into linear spaces, applied in the tangent space of the manifold. Our main contribution consists of showing how to upper bound the final approximation error in the manifold in terms of the intermediate approximation error in the tangent space and a lower bound in the manifold’s sectional curvature. Furthermore, when the sectional curvature is nonnegative, such as for compact Lie groups, the error in the manifold is at least as small as the error in the tangent space. We implement the algorithm in a Julia package