Nonnegatively curved manifolds with souls of codimension 2 (Q1108594)

Let M denote a complete noncompact Riemannian manifold of nonnegative sectional curvature and let S be a soul of M. The author shows that if codim S\(=2\), then there is a Riemannian submersion \(M\to S\), or else the normal bundle of S in M is flat. The author also proves some further related results in more specific situations.