  We study the Bose-Fermi mixture with infinitely boson-boson repulsion and
finite boson-Fermion repulsion. By using a generalized Jordan-Wigner
transformation, we show that the system can be mapped to a repulsive Hubbard
model and thus can be solved exactly for the case with equal boson and fermion
masses. By using the Bethe-ansatz solutions, we investigate the ground state
properties of the mixture system. Our results indicate that the system with
commensurate filling $n=1$ is a charge insulator but still a superfluid with
non-vanishing superfluid density. We also briefly discuss the case with unequal
masses for bosons and fermions.
