  Various prescriptions employed for regulating gauged Nambu--Jona-Lasinio type
models such as the top-quark condensate model are discussed. The use of
dimensional regularization maintains gauge invariance but destroys the
quadratic divergence in the gap equation. If instead a simple ultraviolet
momentum cutoff is used to regulate loop integrals, then gauge invariance is
destroyed by a quadratically divergent term as well as by ambiguities
associated with arbitrary routing of loop momenta. Finally it is shown that one
can use dispersion relations to regulate the top-quark condensate model. This
prescription maintains gauge invariance and does not depend on arbitrary shifts
in loop momenta.
