English

Openness of versality via coherent functors

Algebraic Geometry 2013-04-09 v2

Abstract

We give a proof of openness of versality using coherent functors. As an application, we streamline Artin's criterion for algebraicity of a stack. We also introduce multi-step obstruction theories, employing them to produce obstruction theories for the stack of coherent sheaves, the Quot functor, and spaces of maps in the presence of non-flatness.

Keywords

Cite

@article{arxiv.1206.4182,
  title  = {Openness of versality via coherent functors},
  author = {Jack Hall},
  journal= {arXiv preprint arXiv:1206.4182},
  year   = {2013}
}

Comments

32 pages, revised Introduction

R2 v1 2026-06-21T21:21:50.106Z