  The importance of introducing the SO(5) singlet into the new novel model of
non-Fermi liquid proposed by LeClair and collaborators is pointed out. This
SO(5) singlet order parameter leads to a phase transition between the normal
metal and the pseudogap region in the phase diagram for the anti-ferromagnetic
(AF) phase and the (d-wave) superconducting (SC) phase. A non-zero value for
this order can increase substantially the critical temperature of the SC
transition.
