English

The moduli space of curves is rigid

Algebraic Geometry 2010-03-16 v2

Abstract

We prove that the moduli stack of stable curves of genus g with n marked points is rigid, i.e., has no infinitesimal deformations. This confirms the first case of a principle proposed by Kapranov. It can also be viewed as a version of Mostow rigidity for the mapping class group.

Keywords

Cite

@article{arxiv.math/0509567,
  title  = {The moduli space of curves is rigid},
  author = {Paul Hacking},
  journal= {arXiv preprint arXiv:math/0509567},
  year   = {2010}
}

Comments

11 pages. v2: Proof rewritten to avoid use of log structures. Example of nonrigid moduli space of surfaces added

R2 v1 2026-07-22T17:24:58.377Z