  Recently the revised phase diagram of the (large N) Gross-Neveu model in 1+1
dimensions with discrete chiral symmetry has been determined numerically. It
features three phases, a massless and a massive Fermi gas and a kink-antikink
crystal. Here we investigate the phase diagram by analytical means, mapping the
Dirac-Hartree-Fock equation onto the non-relativistic Schroedinger equation
with the (single gap) Lame potential. It is pointed out that mathematically
identical phase diagrams appeared in the condensed matter literature some time
ago in the context of the Peierls-Froehlich model and ferromagnetic
superconductors.
