ar X iv : m at h / 06 07 35 6 v 1 [ m at h . D G ] 1 4 Ju l 2 00 6 COMPLETE MANIFOLDS WITH NONNEGATIVE
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چکیده
In this short note, as a simple application of the strong result proved recently by Böhm and Wilking, we give a classification on closed manifolds with 2-nonnegative curvature operator. Moreover, by the new invariant cone constructions of Böhm and Wilking, we show that any complete Riemannian manifold (with dimension ≥ 3) whose curvature operator is bounded and satisfies the pinching condition R ≥ δRI > 0, for some δ > 0, must be compact. This provides an intrinsic analogue of a result of Hamilton on convex hypersurfaces.
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تاریخ انتشار 2007