Two-loop diagrams in causal perturbation theory (Q1290557)

In the framework of the causal perturbation theory, proposed by Epstein and Glaser, the possibility of performing higher-order calculations in a compact form is proven, for the two-loop diagrams. The author develops a computing algorithm whose efficiency is tested for scalar QED, standard QED and QCD. The paper contains a short comprehensive introduction of the axiomatic foundation of the method. The vacuum polarization and the electron propagator are calculated. The paper is a good basis for further examples.