A splitting theorem for 4-dimensional manifolds of nonnegative curvature

Walschap, Gerard

doi:10.1090/S0002-9939-1988-0958080-5

A splitting theorem for $4$-dimensional manifolds of nonnegative curvature
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Proc. Amer. Math. Soc. 104 (1988), 265-268 Request permission

Abstract:

A structure theorem for four-dimensional open manifolds of non-negative curvature is stated. More generally, it is shown that any manifold with soul $S$ of codimension 2 admits a Riemannian submersion onto $S$, which splits as a metric product whenever $S$ has flat normal bundle.

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