Zamolodchikov's c function for the chiral Gross-Neveu model

We construct the Zamolodchikov c function for the chiral Gross-Neveu model up to two loops. We show that the c function interpolates between the two known critical points of the theory, it is stationary at them and it decreases with the running coupling constant. In particular one can infer the nonexistence of additional critical points in the region under investigation