  We compute the renormalization group flow of the long-ranged
electron-electron interaction at the Gross-Neveu quantum critical point between
the semimetal and the excitonic insulator in graphene, perturbatively in the
small parameter $\epsilon=d-1$, with $d$ as the spatial dimension. The
$O(\epsilon)$ correction to the usual beta-function makes the long-range
interaction only more irrelevant at the critical than at the Gaussian fixed
point. A weak long-range tail of the Coulomb interaction is found to be
marginally irrelevant also in arbitrary dimension when the number of Dirac
fermions is large. Its ultimate irrelevancy notwithstanding, it is shown that
the metal-insulator transition may still be induced by increasing only the
long-range tail of the Coulomb interaction.
