English

Compact K\"ahler three-folds with nef anti-canonical bundle

Algebraic Geometry 2025-01-09 v3 Complex Variables Differential Geometry

Abstract

In this paper, we prove that a non-projective compact K\"ahler three-fold with nef anti-canonical bundle is, up to a finite \'etale cover, one of the following: a manifold with vanishing first Chern class; the product of a K3 surface and the projective line; or a projective space bundle over a 22-dimensional torus. This result extends Cao-H\"oring's structure theorem for projective manifolds to compact K\"ahler manifolds in dimension 33. For the proof, we investigate the Minimal Model Program for compact K\"ahler three-folds with nef anti-canonical bundles by using the positivity of direct image sheaves, Q\mathbb{Q}-conic bundles, and orbifold vector bundles.

Keywords

Cite

@article{arxiv.2304.03163,
  title  = {Compact K\"ahler three-folds with nef anti-canonical bundle},
  author = {Shin-ichi Matsumura and Xiaojun Wu},
  journal= {arXiv preprint arXiv:2304.03163},
  year   = {2025}
}

Comments

The final version (v3). 39 pages. The term '3-folds' in the title has been changed to ''three-folds'' to align with the publication version. An erroneous argument in Case 1 of Subsection 4.3 has been replaced with a correct alternative proof. To appear in Math. Ann. 391, 1253-1289 (2025)