On Calculation of 1/n Expansions of Critical Exponents in the Gross-Neveu Model with the Conformal Technique

A proof of critical conformal invariance of Green's functions for a quite wide class of models possessing critical scale invariance is given. A simple method for establishing critical conformal invariance of a composite operator, which has a certain critical dimension, is also presented. The method is illustrated with the example of the Gross--Neveu model and the exponents \et\ at order $1/n^3$, \Dl\ and $1/\nu$ at order $1/n^2$ are calculated with the conformal bootstrap method.