Generating functional approach to the Green's functions diagrammatic technique for spin and pseudospin lattice systems II. Diagrammatic method for generalized Pauli operators

A diagrammatic technique for spin and pseudospin lattice systems with complicated single- body levels is developed using the generalized Pauli operators. Rules for the construction and evaluation of the diagrams, representing the zeroth-order many-point irreducible Green's functions are given. The diagrams are constructed with only seven types of vertices and they are considerably simpler than those used up to now. The method formulated in this paper is a continuation of the approach to the spin and pseudospin lattice systems, developed in a previous paper.