English

Noetherian approximation of algebraic spaces and stacks

Algebraic Geometry 2015-10-01 v4

Abstract

We show that every scheme/algebraic space/stack that is quasi-compact with quasi-finite diagonal can be approximated by a noetherian scheme/algebraic space/stack. More generally, we show that any stack which is etale-locally a global quotient stack can be approximated. Examples of applications are generalizations of Chevalley's, Serre's and Zariski's theorems and Chow's lemma to the non-noetherian setting. We also show that every quasi-compact algebraic stack with quasi-finite diagonal has a finite generically flat cover by a scheme.

Keywords

Cite

@article{arxiv.0904.0227,
  title  = {Noetherian approximation of algebraic spaces and stacks},
  author = {David Rydh},
  journal= {arXiv preprint arXiv:0904.0227},
  year   = {2015}
}

Comments

39 pages; complete overhaul of paper; generalized results and simplified proofs (no groupoid-calculations); added more applications and appendices with standard results on constructible properties and limits for stacks; generalized Thm C (no finite presentation hypothesis); some minor changes in 2,1-2.8, 8.2, 8.8 and 8.9; final version

R2 v1 2026-06-21T12:47:14.297Z