Disconnected Reductive Groups: Classification and Representations
Representation Theory
2024-09-20 v1 Group Theory
Abstract
In this article, we classify disconnected reductive groups over an algebraically closed field with a few caveats. Internal parts of our result are both a classification of finite groups and a classification of integral representations of a fixed finite group. Modulo these classifications - which are impossible in different senses - our main result explicitly tabulates the groups with an efficient algorithm. Besides this, we obtain new results about the representation theory of disconnected reductive groups in characteristic zero. We give two descriptions of their representation rings and prove that their Knutson Index is finite.
Cite
@article{arxiv.2409.06375,
title = {Disconnected Reductive Groups: Classification and Representations},
author = {Dylan Johnston and Diego Martín Duro and Dmitriy Rumynin},
journal= {arXiv preprint arXiv:2409.06375},
year = {2024}
}