Continuous Constructive Fermionic Renormalization
  We build the two dimensional Gross-Neveu model by a new method which requires neither cluster expansion nor discretization of phase-space. It simply reorganizes the perturbative series in terms of trees. With this method we can for the first time define non perturbatively the renormalization group differential equations of the model and at the same time construct explicitly their solution. 
M. Disertori, V. Rivasseau (Centre de Physique Theorique, CNRS UPR,   Ecole Polytechnique, France)