We numerically investigated Mott transitions and mixing-demixing transitions
in one-dimensional boson-fermion mixtures at a commensurate filling. The
mixing-demixing transition occurred in a qualitatively similar manner to the
incommensurate filling case. We also found the Mott insulator phase appeared in
both the mixing and the demixing states as the fermion-boson interaction or the
boson-boson interaction increased. Phase diagrams were obtained in the
interaction parameter space