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arXiv · 1806.03006

Etale cohomology, purity and formality with torsion coefficients

Joana Cirici·Geoffroy Horel
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Abstract

We use Galois group actions on étale 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.

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Joana Cirici, Geoffroy Horel. 2025-08-04. Etale cohomology, purity and formality with torsion coefficients. https://doi.org/10.1112/topo.12273

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