Certain general properties of single-particle propagators for a system of interacting fermions are derived. In addition, the properties of the proper self-energy part which were used in previous work on the ground-state energy and on the Fermi surface are established. In particular, the fact that to all orders of perturbation theory in the interaction, behaves like () for very near , is proved.
- Received 1 October 1960
- Published in the issue dated February 1961
© 1961 The American Physical Society