Lifting residual Galois representations with the same semi-simplification
Number Theory
2025-06-17 v1
Abstract
If a -adic Galois representation attached to some eigenform is residually reducible it will have 2 non-isomorphic reductions, which have the same semi-simplification. In this paper, we answer a version of the inverse question, first brought up by Toby Gee and Alice Pozzi. Starting with two modulo non-semi-simple representations , which have the same semi-simplification we show that under some mild conditions that they are reductions of representations attached to newforms of the same weight , the same level , and the same Neben character .
Cite
@article{arxiv.2506.12644,
title = {Lifting residual Galois representations with the same semi-simplification},
author = {Stefan Nikoloski},
journal= {arXiv preprint arXiv:2506.12644},
year = {2025}
}
Comments
50 pages. Comments are welcomed!