The Benson -- Symonds Invariant for Ordinary and Signed Permutation Modules

Abstract

The signed permutation modules are a simultaneous generalization of the ordinary permutation modules and the twisted permutation modules of the symmetric group. In a recent paper Dave Benson and Peter Symonds defined a new invariant ${\gamma }_G(M)$ for a finite dimensional module $M$ of a finite group $G$ which attempts to quantify how close a module is to being projective. In this paper, we determine this invariant for all the signed permutation modules of the symmetric group using tools from representation theory and combinatorics.

14 pages. arXiv admin note: substantial text overlap with arXiv:2012.00341