  We construct the phase diagram of the quark-antiquark and diquark condensates
at finite temperature and density in the 2 + 1 dimensional (3D) two flavor
massless Gross Neveu (GN) model with the 4-component quarks. In contrast to the
case of the 2-component quarks, there appears the coexisting phase of the
quark-antiquark and diquark condensates. This is the crucial difference between
the 2-component and 4-component quark cases in the 3D GN model. The coexisting
phase is also seen in the 4D Nambu Jona-Lasinio model. Then we see that the 3D
GN model with the 4-component quarks bears closer resemblance to the 4D Nambu
Jona-Lasinio model.
