  We consider a Kondo-like impurity interacting with fermions on a honeycomb
lattice at half-filling, as in the case of graphene. We derive from the lattice
model an effective one-dimensional continuum theory which has, in general, four
flavors with angular momentum mixing in the presence of internode scattering
processes and six couplings in the spin-isotropic case. Under particular
conditions, however, it can be reduced to a single-coupling multichannel
pseudogap Kondo model. We finally calculate, in the presence of an energy
dependent Fermi velocity, induced by Coulomb interaction, the critical coupling
in the large-N expansion, the magnetic susceptibility and the specific heat.
