On positivity of the CM line bundle on K-moduli spaces
Chenyang Xu, Ziquan Zhuang
Abstract
In this paper, we consider the CM line bundle on the K-moduli space, i.e., the moduli space parametrizing K-polystable Fano varieties. We prove it is ample on any proper subspace parametrizing reduced uniformly K-stable Fano varieties that conjecturally should be the entire moduli space. As a corollary, we prove that the moduli space parametrizing smoothable K-polystable Fano varieties is projective. During the course of proof, we develop a new invariant for filtrations that can be used to test various K-stability notions of Fano varieties.
Topics & Concepts
Fano planeMathematicsModuli spaceLine bundleBundleInvariant (physics)Pure mathematicsSubspace topologyModuliSpace (punctuation)Geometric invariant theoryLine (geometry)Mathematical analysisModuli of algebraic curvesLinear subspaceGeometry and complex manifoldsAlgebraic Geometry and Number TheoryGeometric and Algebraic Topology