Single Scale Analysis of Many Fermion Systems. Part 2: The First Scale
  The first renormalization group map arising from the momentum space decomposition of a weakly coupled system of fermions at temperature zero differs from all subsequent maps. Namely, the component of momentum dual to temperature may be arbitrarily large - there is no ultraviolet cutoff. The methods of Part 1 are supplemented to control this special case. 
Joel Feldman, Horst Knoerrer and Eugene Trubowitz