  We consider the most general four fermion operators in QCD for two and three
massless flavors and study their renormalization in the vicinity of the Fermi
surface. We show that, asymptotically, the largest coupling corresponds to
scalar diquark condensation. Asymptotically the direct and iterated (molecular)
instanton interactions become equal. We provide simple arguments for the form
of the operators that diagonalize the evolution equations. Some solutions of
the flow equations exhibit instabilities arising out of purely repulsive
interactions.
