Renormalization of Quantum Electrodynamics and Hopf Algebras
  In 1999, A. Connes and D. Kreimer have discovered the Hopf algebra structure on the Feynman graphs of scalar field theory. They have found that the renormalization can be interpreted as a solving of some Riemann -- Hilbert problem. In this work a generalization of their scheme to the case of quantum electrodynamics is proposed. The action of the gauge group on the Hopf algebra of diagrams are defined and the proof that this action is consistent with the Hopf algebra structure is given. 
D.V. Prokhorenko, I.V. Volovich