Character bounds for finite groups of Lie type

We establish new bounds on character values and character ratios for finite groups G of Lie type, which are considerably stronger than previously known bounds, and which are best possible in many cases. These bounds have the form |χ(g)|⩽cχ(1)αg, and give rise to a variety of applications, for exampl...

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Bibliographic Details
Main Authors: Bezrukavnikov, Roman, Liebeck, Martin W., Shalev, Aner, Tiep, Pham Huu
Other Authors: Massachusetts Institute of Technology. Department of Mathematics
Format: Article
Language:English
Published: International Press of Boston 2021
Online Access:https://hdl.handle.net/1721.1/122808.2
Description
Summary:We establish new bounds on character values and character ratios for finite groups G of Lie type, which are considerably stronger than previously known bounds, and which are best possible in many cases. These bounds have the form |χ(g)|⩽cχ(1)αg, and give rise to a variety of applications, for example to covering numbers and mixing times of random walks on such groups. In particular, we deduce that, if G is a classical group in dimension n, then, under some conditions on G and g∈G, the mixing time of the random walk on G with the conjugacy class of g as a generating set is (up to a small multiplicative constant) n/s, where s is the support of g.