PSL(3,2) Modulo 7

The Hecke algebra for the Projective Special Linear Group of dimension 3 over GF(2) with point stabilizer being the normalizer of a Sylow 7-subgroup in characteristic 7 .

The Module M

The module M is the permutation module over the prime field of chacteristic 7, having point stablilizer of order 21 The dimension of M is 8 .

The dimensions of the irreducible submodules modules are 7, 1 .

The module M has radical filtration (Loewy series)
1, 2


The module M has socle filtration (socle series)
1, 2


The Action Algebra

The action algebra A is the image of kG in the k-endomorphism ring of M. It's simple modules are the irreducible submodules of M.

The dimensions of the projective modules are 7, 1 .

The cartan matrix of A is



The determinant of the Cartan matrix is 1.

The blocks of A consist of the following irreducible modules: