English

Etale cohomology, purity and formality with torsion coefficients

Algebraic Topology 2025-08-05 v2

Abstract

We use Galois group actions on \'etale cohomology to prove results of formality for dg-operads and dg-algebras with torsion coefficients. Our theory applies, among other related constructions, to the dg-operad of singular chains on the operad of little disks and to the dg-algebra of singular cochains on the configuration space of points in the complex space. The formality that we obtain is only up to a certain degree, which depends on the cardinality of the field of coefficients.

Keywords

Cite

@article{arxiv.1806.03006,
  title  = {Etale cohomology, purity and formality with torsion coefficients},
  author = {Joana Cirici and Geoffroy Horel},
  journal= {arXiv preprint arXiv:1806.03006},
  year   = {2025}
}

Comments

25 pages. This is a corrected version of the published version (see the note at the begining)