  The group algebra of the permutation group is spanned by a set of elements
called projectors. The coordinates of permutations expanded in projectors are
matrix elements of irreducible representations. The projectors of the
permutation group are a product of a Young symmetriser and a Young
antisymmetriser. They form non-orthogonal bases of right and left modules. The
non-orthogonality is compensated by a constant matrix. It turns out that this
reduces the matrix entries to -1, 0,+1. An algorithm to compute the projectors
is given.
