English

Families of Log Canonically Polarized Varieties

Algebraic Geometry 2011-05-17 v1

Abstract

Determining the number of singular fibers in a family of varieties over a curve is a generalization of Shafarevich's Conjecture and has implications for the types of subvarieties that can appear in the corresponding moduli stack. We consider families of log canonically polarized varieties over 1\P^1, i.e. families g:(Y,D)1g:(Y,D)\to \P^1 where DD is an effective snc divisor and the sheaf ωY/1(D)\omega_{Y/\P^1}(D) is gg-ample. After first defining what it means for fibers of such a family to be singular, we show that with the addition of certain mild hypotheses (the fibers have finite automorphism group, \sOY(D)\sO_Y(D) is semi-ample, and the components of DD must avoid the singular locus of the fibers and intersect the fibers transversely), such a family must either be isotrivial or contain at least 3 singular fibers.

Keywords

Cite

@article{arxiv.1105.3102,
  title  = {Families of Log Canonically Polarized Varieties},
  author = {Ariana Dundon},
  journal= {arXiv preprint arXiv:1105.3102},
  year   = {2011}
}