Reduction of manifolds with semi-negative holomorphic sectional curvature
arXiv:1705.00605
Abstract
In this note, we continue the investigation of a projective Kähler manifold of semi-negative holomorphic sectional curvature . We introduce a new differential geometric numerical rank invariant which measures the number of linearly independent {\it truly flat} directions of in the tangent spaces. We prove that this invariant is bounded above by the nef dimension and bounded below by the numerical Kodaira dimension of . We also prove a splitting theorem for in terms of the nef dimension and, under some additional hypotheses, in terms of the new rank invariant.