We study norm convergence and summability of Fourier series in the setting of
reduced twisted group $C^*$-algebras of discrete groups. For amenable groups,
F{\o}lner nets give the key to Fej\'er summation. We show that Abel-Poisson
summation holds for a large class of groups, including e.g. all Coxeter groups
and all Gromov hyperbolic groups. As a tool in our presentation, we introduce
notions of polynomial and subexponential H-growth for countable groups w.r.t.
proper scale functions, usually chosen as length functions. These coincide with
the classical notions of growth in the case of amenable groups.
@article{0605145,
author = {Bedos, Erik and Conti, Roberto},
title = {On twisted Fourier analysis and convergence of Fourier series on
discrete groups},
journal = {arXiv},
volume = {2006},
number = {0},
year = {2006},
language = {en},
url = {http://dml.mathdoc.fr/item/0605145}
}
Bedos, Erik; Conti, Roberto. On twisted Fourier analysis and convergence of Fourier series on
discrete groups. arXiv, Tome 2006 (2006) no. 0, . http://gdmltest.u-ga.fr/item/0605145/