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

TL;DR

This paper introduces an axiomatic approach to Kodaira dimension, classifies geometries in low dimensions, and explores its relation to simplicial volume and holomorphic properties in complex manifolds.

Contribution

It provides a new axiomatic definition for Kodaira dimension, classifies Thurston geometries up to dimension 5, and links simplicial volume with holomorphic Kodaira dimension.

Findings

Kodaira dimension is monotone under degree-one maps in 5-manifolds.

Established a connection between simplicial volume and holomorphic Kodaira dimension.

Showed that Kähler 3-folds with non-zero simplicial volume have maximal Kodaira dimension.

Abstract

We introduce an axiomatic definition for the Kodaira dimension and classify Thurston geometries in dimensions $\leq 5$ 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 K\"ahler 3-fold with non-vanishing simplicial volume has top holomorphic Kodaira dimension.