English

Compactifications of moduli of points and lines in the projective plane

Algebraic Geometry 2021-07-13 v2

Abstract

Projective duality identifies the moduli spaces Bn\mathbf{B}_n and X(3,n)\mathbf{X}(3,n) parametrizing linearly general configurations of nn points in P2\mathbb{P}^2 and nn lines in the dual P2\mathbb{P}^2, respectively. The space X(3,n)\mathbf{X}(3,n) admits Kapranov's Chow quotient compactification X(3,n)\overline{\mathbf{X}}(3,n), studied also by Lafforgue, Hacking, Keel, Tevelev, and Alexeev, which gives an example of a KSBA moduli space of stable surfaces: it carries a family of certain reducible degenerations of P2\mathbb{P}^2 with nn "broken lines". Gerritzen and Piwek proposed a dual perspective, a compact moduli space parametrizing certain reducible degenerations of P2\mathbb{P}^2 with nn smooth points. We investigate the relation between these approaches, answering a question of Kapranov from 2003.

Keywords

Cite

@article{arxiv.2010.03519,
  title  = {Compactifications of moduli of points and lines in the projective plane},
  author = {Luca Schaffler and Jenia Tevelev},
  journal= {arXiv preprint arXiv:2010.03519},
  year   = {2021}
}

Comments

66 pages. Final version. To appear in International Mathematics Research Notices