Pak-Yeung Chan (University of Warwick) Gap theorem for nonnegatively curved manifolds Abstract: In this seminar, we shall discuss some recent results on the gap theorem of nonnegatively curved manifolds with small curvature in an average integral sense, which can be viewed as a Riemannian analogue of the optimal gap result by Ni on Kaehler manifolds. In dimension 3, we also establish a gap theorem for Ricci nonnegative manifolds with pointwise quadratic curvature decay and fast average integral curvature decay. This talk is based on some joint works with Man-Chun Lee.