English

Big $q$-ample Line Bundles

Algebraic Geometry 2019-02-20 v1

Abstract

A recent paper of Totaro develops a theory of qq-ample bundles in characteristic 0. Specifically, a line bundle LL on XX is qq-ample if for every coherent sheaf F\mathcal{F} on XX, there exists an integer m0m_0 such that mm0m\geq m_0 implies Hi(X,FO(mL))=0H^i(X,\mathcal{F}\otimes \mathcal{O}(mL))=0 for i>qi>q. We show that a line bundle LL on a complex projective scheme XX is qq-ample if and only if the restriction of LL to its augmented base locus is qq-ample. In particular, when XX is a variety and LL is big but fails to be qq-ample, then there exists a codimension 1 subscheme DD of XX such that the restriction of LL to DD is not qq-ample.

Keywords

Cite

@article{arxiv.1105.3449,
  title  = {Big $q$-ample Line Bundles},
  author = {Morgan V Brown},
  journal= {arXiv preprint arXiv:1105.3449},
  year   = {2019}
}

Comments

9 pages, 2 pdf figures

R2 v1 2026-06-21T18:08:42.276Z