Roots of unity in $K(n)$-local rings
Abstract
The goal of this paper is to address the following question: if is an -ring for some and is a map of commutative rings, when can we find an -ring with an -ring map such that ? A classical result in the theory of realizing -rings, due to Goerss--Hopkins, gives an affirmative answer to this question if is etale. The goal of this paper is to provide answers to this question when is ramified. We prove a non-realizability result in the -local setting for every for -rings containing primitive th roots of unity. As an application, we give a proof of the folk result that the Lubin--Tate tower from arithmetic geometry does not lift to a tower of -rings over Morava -theory.
Keywords
Cite
@article{arxiv.1707.09957,
title = {Roots of unity in $K(n)$-local rings},
author = {Sanath K. Devalapurkar},
journal= {arXiv preprint arXiv:1707.09957},
year = {2019}
}
Comments
7 pages; improved introduction; version accepted by Proc. Amer. Math. Soc