1/N Expansion for Horava-Lifshitz like four-fermion models

We study a class of four-fermion Gross–Neveu like models in four dimensions with critical exponents $$z=2$$ and $$z=3$$. The models with $$z=2$$ are in general perturbatively nonrenormalizable but we show that there are in special cases renormalizable in the context of the 1/N expansion. We calculate explicitly the effective potential for these models.