English

Non-polyhedral effective cones from the moduli space of curves

Algebraic Geometry 2021-01-14 v2

Abstract

We show that the pseudoeffective cone of divisors Eff1(Mg,n)\overline{\text{Eff}}^1(\overline{\mathcal{M}}_{g,n}) for g2g\geq 2 and n2n\geq 2 is not polyhedral by showing that the class of the fibre of the morphism forgetting one point forms an extremal ray of the dual nef cone of curves Nef1(Mg,n)\overline{\text{Nef}}_1(\overline{\mathcal{M}}_{g,n}) and the cone at this ray is not polyhedral.

Keywords

Cite

@article{arxiv.2001.08204,
  title  = {Non-polyhedral effective cones from the moduli space of curves},
  author = {Scott Mullane},
  journal= {arXiv preprint arXiv:2001.08204},
  year   = {2021}
}

Comments

17 pages, 4 figures