Positive projectively flat manifolds are locally conformally flat-Kahler Hopf manifolds

We define a partition of the space of projectively flat metrics in three classes according to the sign of the Chern scalar curvature; we prove that the class of negative projectively flat metrics is empty, and that the class of positive projectively flat metrics consists precisely of locally conformally flat-Kahler metrics on Hopf manifolds, explicitly characterized by Vaisman [23]. Finally, we review the known characterization and properties of zero projectively flat metrics. As applications, we make sharp a list of possible projectively flat metrics by Li, Yau, and Zheng [16, Theorem 1]; moreover we prove that projectively flat astheno-Kahler metrics are in fact Kahler and globally conformally flat.