  The recently proposed construction of chiral fermions on lattices with
boundaries is tested in an interacting theory up to first order of perturbation
theory. We confirm that, in the bulk of the lattice, the chiral Ward identities
take their continuum value up to cutoff effects without any tuning. Universal
quantities are defined that have an expansion in the renormalised couplings
with coefficients that are functions of the physical size and the periodicity
in the spatial direction. These coefficient functions have to be identical for
different discretisations. We find agreement with the standard Wilson fermions.
The computation is done in the asymptotically free Gross-Neveu model with
continuous chiral symmetry.
