Department of Mathematics, University of Pennsylvania, Philadelphia, Pennsylvania 19104 ; Department of Mathematics, University of Oklahoma, Norman, Oklahoma 73019
Abstract:
We study geometric properties of the metric projection of an open manifold with nonnegative sectional curvature onto a soul . is shown to be up to codimension 3. In arbitrary codimensions, small metric balls around a soul turn out to be convex, so that the unit normal bundle of also admits a metric of nonnegative curvature. Next we examine how the horizontal curvatures at infinity determine the geometry of , and study the structure of Sharafutdinov lines. We conclude with regularity properties of the cut and conjugate loci of .