English

Compact K\"{a}hler manifolds with partially semi-positive curvature

Differential Geometry 2026-03-09 v4 Algebraic Geometry Complex Variables

Abstract

In this paper, we study MRC fibrations of compact K\"ahler manifolds with partially semi-positive curvature. We first prove that a compact K\"ahler manifold is rationally connected if its tangent bundle is BC-pp positive for all 1pdimX1\leq p\leq \dim X. As applications, we confirm a conjecture that any compact K\"ahler manifold with positive orthogonal Ricci curvature must be rationally connected, and generalize a result of Heier-Wong and Yang to the conformally K\"ahler case. The second result concern structure theorems for two immediate curvature conditions. We prove that, a compact K\"ahler manifold with kk-semi-positive Ricci curvature or semi-positive kk-scalar curvature, either the rational dimension nk+1\geq n-k+1 or it admits a locally constant fibration f:XYf: X\rightarrow Y such that the fibre is rationally connected and the image YY is Ricci-flat.

Keywords

Cite

@article{arxiv.2504.13155,
  title  = {Compact K\"{a}hler manifolds with partially semi-positive curvature},
  author = {Shiyu Zhang and Xi Zhang},
  journal= {arXiv preprint arXiv:2504.13155},
  year   = {2026}
}

Comments

29 pages, final version: typos corrected, to appear in the Transactions of the American Mathematical Society