Manifolds with positive orthogonal Ricci curvature

Abstract

In this paper we study the class of compact K\ahler manifolds with positive orthogonal Ricci curvature: $Ric^\perp>0$. First we illustrate examples of K\ahler manifolds with $Ric^\perp>0$ on K\ahler C-spaces, and construct ones on certain projectivized vector bundles. These examples show the abundance of K\ahler manifolds which admit metrics of $Ric^\perp>0$. Secondly we prove some (algebraic) geometric consequences of the condition $Ric^\perp>0$ to illustrate that the condition is also quite restrictive. Finally this last point is made evident with a classification result in dimension three and a partial classification in dimension four.