2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/22863The hierarchy of Green functions for (quasi)degenerate systems, presented in cond-mat/0308058, is calculated in detail for the case of a system with closed shells plus a single electron in a two-fold degenerate level. The complete hierarchy is derived explicitly, in terms of Green functions and of Feynman diagrams.9 pages, 1 figureStrongly Correlated Electronstext