A Proof of Luttinger Theorem
  A rigorous and simple perturbative proof of Luttinger's theorem is sketched for Fermi liquids in two and three dimensions. It is proved that in the finite volume, the quasi-particle density is independent of the interaction strength. The thermodynamic limit is then controlled to all orders in perturbation theory. 
A. Praz, J. Feldman, H. Knoerrer and E. Trubowitz