On the structure of affine flat group schemes over discrete valuation rings, II
Abstract
In the 1st part of this work [DHdS18], we studied affine group schemes over a discrete valuation ring (DVR) by means of Neron blowups. We also showed how to apply these findings to throw light on the group schemes coming from Tannakian categories of D-modules. In the present work, we follow up this theme. We show that a certain class of affine group schemes of "infinite type", Neron blowups of formal subgroups, are quite typical. We also explain how these group schemes appear naturally in Tannakian categories of D-modules. To conclude, we isolate a Tannakian property of affine group schemes, named prudence, which allows one to verify if the underlying ring of functions is a free module over the base ring. This is then successfully applied to obtain a general result on the structure of differential Galois groups over complete DVRs.
Keywords
Cite
@article{arxiv.1802.06377,
title = {On the structure of affine flat group schemes over discrete valuation rings, II},
author = {Phùng Hô Hai and João Pedro dos Santos},
journal= {arXiv preprint arXiv:1802.06377},
year = {2022}
}
Comments
32 pages, final version, to appear in Int. Math. Res. Notices