PSL(2,16) Modulo 17

The Hecke algebra for the Projective Special Linear Group of dimension 2 over GF(16) with point stabilizer being the normalizer of a Sylow 17-subgroup in characteristic 17 .

The Module M

The module M is the permutation module over the field of chacteristic 17, having point stablilizer of order 34 . The dimension of M is 120 .

The dimensions of the irreducible submodules are 68, 34, 17, 1 .

The module is semi-simple. It has composition factors consisting of the modules 1, 2, 3, 4.

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 algebra A is a direct product of matrix algebras of dimension 17, 17, 17, 1 over field extensions of the prime field of degrees 4, 2, 1, 1 .