HomGModule( module1, module2 )
This function can only be run if IsIrreducible(module1) has returned
true. module1 and module2 are assumed to be G-modules for the
same group G, and a basis of the space of G-homomorphisms from
module1 to module2 is calculated and returned. Each homomorphism in
this list is given as a d_1 times d_2 matrix, where d_1 and d_2
are the dimensions of module1 and module2; the rows of the matrix are
the images of the standard basis of module1 in module2 under the
homomorphism.
GAP 3.4.4