Correlation pseudogaps in HTSC
  The electronic correlations in oxide HTSC in the normal state are analyzed by the generalized Hartree-Fock theory of Nambu and Gorkov. It yields two kinds of pseudogaps, the small pseudogap (SPG) and the large pseudogap (LPG). The first is obtained by the Fock integral, and the second by the Hartree integral. We find real gaps for the undoped materials, and pseudogaps for the doped and conducting ones. The latter result in the V- shaped experimental density of states. 
Moshe Dayan