  We explore the renormalization group flow of quartic perturbations in the
low-energy theory of graphene, in the strong Coulomb coupling and large-N
limits, where N is the number of fermion flavors. We compute the anomalous
dimensions of the quartic couplings u up to next-to-leading order in 1/N and
find both relevant and irrelevant directions in the space of quartic couplings.
We discuss possible phase diagrams and relevance for the physics of graphene.
