[en] The model describd by a Lagrangian is studied in 1+l dimensions. Wilson's renormalization prescription is adopted and a nontrivial infrared stable fixed point is obtained in the mean field approximation. It is demonstrated that at the fixed point the operators sigma delta²sigma and g/sub on/sigma/sup n/ for n = 4,6,...infinity become irrelevant and the theory becomes equivalent to the Gross-Neveu model. The equivalence is independent of the values of the dimensionless bare couplings of the original model (universality). Similar results are obtained in the case of other models in 3+l dimensions