  Recently, it has been suggested that large-Nc orbifold equivalences may be
applicable to certain theories with chemical potentials, including QCD, in
certain portions of their phase diagram. When valid, such an equivalence offers
the possibility of relating large-Nc QCD at non-zero baryon chemical potential,
a theory with a complex fermion determinant, to a related theory whose fermion
determinant is real and positive. In this paper, we provide a test of this
large Nc equivalence using a holographic realization of a supersymmetric theory
with baryon chemical potential and a related theory with isospin chemical
potential. We show that the two strongly-coupled, large-Nc theories are
equivalent in a large region of the phase diagram.
