  We use simple iterated one-loop graphs in massless Yukawa theory and QED to
pose the following question: what are the symmetries of the residues of a graph
under a permutation of places to insert subdivergences. The investigation
confirms partial invariance of the residue under such permutations: the highest
weight transcendental is invariant under such a permutation. For QED this
result is gauge invariant, ie the permutation invariance holds for any gauge.
Computations are done making use of the Hopf algebra structure of graphs and
employing GiNaC to automate the calculations.
