ON LATTICES OF INTEGRAL GROUP ALGEBRAS AND SOLOMON ZETA FUNCTIONS

Year 2019, Volume: 25 Issue: 25, 129 - 170, 08.01.2019

Susanne Danz Tommy Hofmann

https://doi.org/10.24330/ieja.504139

https://izlik.org/JA96SX86TP

Abstract

We investigate integral forms of certain simple modules over group algebras in characteristic 0 whose

$p$-modular reductions have precisely three composition factors. As a consequence we, in particular, complete

the description of the integral forms of the simple $\QQ\mathfrak{S}_n$-module labelled by the hook partition $(n-2,1^2)$.

Moreover, we investigate the integral forms of the Steinberg module of finite special linear groups $\PSL_2(q)$

over suitable fields of characteristic 0. In the second part of the paper we explicitly determine the Solomon zeta functions

of various families of modules and lattices over group algebra, including Specht modules of symmetric groups labelled by

hook partitions and the Steinberg module of $\PSL_2(q)$.

Keywords

Integral representation , lattice , Jordan–Zassenhaus , symmetric group , Specht module , hook partition , projective special linear group , Steinberg module , Solomon zeta function

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