English

Galois actions on homotopy groups

Algebraic Geometry 2014-11-11 v4 Algebraic Topology Number Theory

Abstract

We study the Galois actions on the l-adic schematic and Artin-Mazur homotopy groups of algebraic varieties. For proper varieties of good reduction over a local field K, we show that the l-adic schematic homotopy groups are mixed representations explicitly determined by the Galois action on cohomology of Weil sheaves, whenever l is not equal to the residue characteristic p of K. For quasi-projective varieties of good reduction, there is a similar characterisation involving the Gysin spectral sequence. When l=p, a slightly weaker result is proved by comparing the crystalline and p-adic schematic homotopy types. Under favourable conditions, a comparison theorem transfers all these descriptions to the Artin-Mazur homotopy groups.

Keywords

Cite

@article{arxiv.0712.0928,
  title  = {Galois actions on homotopy groups},
  author = {J. P. Pridham},
  journal= {arXiv preprint arXiv:0712.0928},
  year   = {2014}
}

Comments

72 pages; v2 corrections to Section 3; v3 references updated; v4 final version

R2 v1 2026-06-21T09:51:12.283Z