English

A note on \'etale $(\varphi,\Gamma)$-modules in families

Number Theory 2024-05-14 v1

Abstract

Let Λ\Lambda be a complete noetherian local ring with finite residue field of characteristic pp and K/QpK/\mathbb{Q}_p a pp-adic field. We show that, by deformation of the structure sheaf on the (transversal) prismatic site of a bounded pp-adic formal scheme X\mathfrak{X}, the category of prismatic (Λ,F)(\Lambda,F)-crystals on X\mathfrak{X} is equivalent to Λ\Lambda-\'etale local systems on the generic adic fiber of X\mathfrak{X} and that the cohomology of (Λ,F)(\Lambda,F)-crystals recovers the pro-\'etale cohomology of the corresponding local systems. The proof follows the strategy used in \cite{bhatt2023prismatic} and \cite{marks2023prismatic}. From this we construct an isomorphism between Iwasawa cohomology of a pp-adic Lie extension of KK and prismatic cohomology. Following \cite{wu2021galois}, we then reprove Dee's classical result \cite{article} on the equivalence between families of Galois representations and \'etale (φ,Γ)(\varphi,\Gamma)-modules.

Keywords

Cite

@article{arxiv.2405.07654,
  title  = {A note on \'etale $(\varphi,\Gamma)$-modules in families},
  author = {Marvin Schneider},
  journal= {arXiv preprint arXiv:2405.07654},
  year   = {2024}
}

Comments

11 pages

R2 v1 2026-06-28T16:25:14.116Z