  We use a path integral approach to calculate the superfluid density of a Bose
lattice gas in the limit where the number of atoms per site is large. Our
analytical expressions agree with numerical results on small systems for low
temperatures and relatively weak interactions. We also calculate the superfluid
density and drag for two-component lattice bosons. To attain the correct
results we develop tools for calculating discrete time path integrals. These
tools should be broadly applicable to a range of systems which are naturally
described within an overcomplete basis.
