  We extend the dual algorithm recently described for pure, non-abelian
Yang-Mills on the lattice to the case of lattice fermions coupled to
Yang-Mills, by constructing an ergodic Metropolis algorithm for dynamic
fermions that is local, exact, and built from gauge-invariant boson-fermion
coupled configurations. For concreteness, we present in detail the case of
three dimensions, for the group SU(2) and staggered fermions, however the
algorithm readily generalizes with regard to group and dimension. The treatment
of the fermion determinant makes use of a polymer expansion; as with previous
proposals making use of the polymer expansion in higher than two dimensions,
the critical question for practical applications is whether the presence of
negative amplitudes can be managed in the continuum limit.
