SpinBasis( vector, matrices )
The input is a vector, vector, and a list of n times n matrices, matrices, where n is the length of the vector. A normalised basis of the submodule generated by the action of the matrices (acting on the right) on the vector is calculated and returned. It is returned as an r times n matrix, where r is the dimension of this submodule.
SpinBasis is called by IsIrreducible.
GAP 3.4.4