Geometric structures, the Gromov order, Kodaira dimensions and simplicial volume

Abstract

We introduce an axiomatic definition for the Kodaira dimension and classify Thurston geometries in dimensions ≤ 5 in terms of this Kodaira dimension. We show that the Kodaira dimension is monotone with respect to the partial order defined by maps of non-zero degree between 5-manifolds. We study the compatibility of our definition with traditional notions of Kodaira dimension, especially the highest possible Kodaira dimension. To this end, we establish a connection between the simplicial volume and the holomorphic Kodaira dimension, which in particular implies that any smooth Kähler 3-fold with nonvanishing simplicial volume has top holomorphic Kodaira dimension.