A generalization of Hamilton's differential Harnack inequality for the Ricci flow

Abstract

In [10], R. Hamilton established a differential Harnack inequality for solutions to the Ricci flow with nonnegative curvature operator. We show that this inequality holds under the weaker condition that M x R^2 has nonnegative isotropic curvature.

revised version, to appear in J. Diff. Geom