English

Local constancy of pro-unipotent Kummer maps

Algebraic Geometry 2022-06-20 v2 Number Theory

Abstract

It is a theorem of Kim-Tamagawa that the Q\mathbb Q_\ell-pro-unipotent Kummer map associated to a smooth projective curve YY over a finite extension of Qp\mathbb Q_p is locally constant when p\ell\neq p. The present paper establishes two generalisations of this result. Firstly, we extend the Kim-Tamagawa Theorem to the case that YY is a smooth variety of any dimension. Secondly, we formulate and prove the analogue of the Kim-Tamagawa Theorem in the case =p\ell = p, again in arbitrary dimension. In the course of proving the latter, we give a proof of an \'etale-de Rham comparison theorem for pro-unipotent fundamental groupoids using methods of Scholze and Diao-Lan-Liu-Zhu. This extends the comparison theorem proved by Vologodsky for certain truncations of the fundamental groupoids.

Keywords

Cite

@article{arxiv.2203.03701,
  title  = {Local constancy of pro-unipotent Kummer maps},
  author = {L. Alexander Betts},
  journal= {arXiv preprint arXiv:2203.03701},
  year   = {2022}
}

Comments

31 pages, comments welcome

R2 v1 2026-06-24T10:05:13.574Z