Comment on ``Quasiparticle Anisotropy and Pseudogap Formation from the   Weak-Coupling Renormalization Group Point of View''
  In their recent Letter (Phys. Rev. Lett., Vol. 93, 106406 (2004)), Katanin and Kampf reported numerical results for the self-energy Sigma(k;e), at real values of e, of the single-band Hubbard Hamiltonian in two space dimensions, obtained through employing the functional renormalization-group (fRG) formalism at the one-loop level. Several of the results by Katanin and Kampf are in full conformity with the exact formal results reported earlier by the present author. This, as we shall elaborate in this contribution, strengthens one's confidence in the reliability of the fRG in dealing with models of strongly-correlated fermions. 
Behnam Farid