Double permutation method of designing Feynman diagrams for mass operator of interacting electrons

摘要

We introduce the systematic algebraic method of designing Feynman diagrams for mass operator (MO) of interacting electrons, based on permutation group theory. It permits to design Feynman diagrams for MO directly without disconnected or singly connected diagrams and insist that all possible expressions are presented. Using the developed method Feynman diagrams were designed for MO of the first four orders of perturbation theory.