English

Boundedness of hyperbolic varieties

Algebraic Geometry 2023-06-26 v2 Number Theory

Abstract

Let kk be an algebraically closed field of characteristic zero, and let X/kX/k be a projective variety. The conjectures of Demailly--Green--Griffiths--Lang posit that every integral subvariety of XX is of general type if and only if XX is algebraically hyperbolic i.e., for any ample line bundle L\mathcal{L} on XX there is a real number α(X,L)\alpha(X,\mathcal{L}), depending only on XX and L\mathcal{L}, such that for every smooth projective curve C/kC/k of genus g(C)g(C) and every kk-morphism f ⁣:CXf\colon C\to X, degCfLα(X,L)g(C)\text{deg}_Cf^*\mathcal{L} \leq \alpha(X,\mathcal{L})\cdot g(C) holds. In this work, we prove that if X/kX/k is a projective variety such that every integral subvariety is of general type, then for every ample line bundle L\mathcal{L} on XX and every integer g0g\geq 0, there is an integer α(X,L,g)\alpha(X,\mathcal{L},g), depending only on X,L,X,\mathcal{L}, and gg, such that for every smooth projective curve C/kC/k of genus gg and every kk-morphism f ⁣:CXf\colon C\to X, the inequality degCfLα(X,L,g)\text{deg}_Cf^*\mathcal{L} \leq \alpha(X,\mathcal{L},g) holds, or equivalently, the Hom-scheme Homk(C,X)\underline{\text{Hom}}_k(C,X) is projective.

Keywords

Cite

@article{arxiv.2209.09982,
  title  = {Boundedness of hyperbolic varieties},
  author = {Jackson S. Morrow},
  journal= {arXiv preprint arXiv:2209.09982},
  year   = {2023}
}

Comments

v2: 41 pages. Significant updates throughout to address several mistakes in previous version. Results remain unchanged. Comments are welcome!

R2 v1 2026-06-28T01:46:18.163Z