  In this paper it is shown that many of the observables in QED-type theories
can be realized in terms of a combinatorial structure called chord diagrams.
One major advantage of this representation is that the asymptotic behaviour of
the corresponding Green functions can be captured completely without appealing
to the usual approach of singularity analysis. This relation also reveals the
unexplained correlation between the number of diagrams in Yukawa theory and the
diagrams in quenched QED.
