---
abstract: 'Let $G(q)$ be a Chevalley group over a finite field ${{\mathbb{F}}}_q$. By Lusztig’s and Shoji’s work, the problem of computing the values of the unipotent characters of $G(q)$ is solved, in principle, by the theory of character sheaves; one issue in this solution is the determination of certain scalars relating two types of class functions on $G(q)$. We show that this issue can be reduced to the case where $q$ is a prime, which opens the way to use computer algebra methods. Here, and in a sequel to this article, we use this approach to solve a number of cases in groups of exceptional type which seemed hitherto out of reach.'
address: |
    IAZ - Lehrstuhl für Algebra\
    Universität Stuttgart\
    Pfaffenwaldring 57\
    D–70569 Stuttgart\
    Germany
author:
- Meinolf Geck
date: 'November 11, 2017'
title: On the values of unipotent characters in bad characteristic
---

Introduction {#sec0}
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Let $G(q)$ be a group of Lie type over a finite field with $q$ elements. This paper is concerned with the problem of computing the values of the irreducible characters of $G(q)$. The work of Lusztig [@L1], [@Lintr] has led to a general program for solving this problem. In this framework, 