Manifolds with positive isotropic curvature of dimension at least nine

Abstract

In [Bre19], Simon Brendle showed that any compact manifold of dimension $n\geq12$ with positive isotropic curvature and contains no nontrivial incompressible $(n-1)-$dimensional space form is diffeomorphic to a connected sum of finitely many spaces, each of which is a quotient of $S^n$ or $S^{n-1}\times \mathbb{R}$ by standard isometries. We show that this result is actually true for $n\geq9$.