Four-loop verification of an algorithm for summing Feynman diagrams in the $N{=}1$ supersymmetric electrodynamics

By calculating some four-loop diagrams in the $N{=}1$ supersymmetric electrodynamics regularized by higher derivatives, we verify a method for summing Feynman diagrams based on using Schwinger–Dyson equations and Ward identities. In particular, for the diagrams considered, we prove the correctness of an additional identity for Green's functions not reduced to the gauge Ward identity.