Improved Lower Bounds on the Ground-State Entropy of the Antiferromagnetic Potts Model

We present generalized methods for calculating lower bounds on the ground-state entropy per site, $S_0$, or equivalently, the ground-state degeneracy per site, $W=e^{S_0\mathrm{/}{k}_B}$, of the antiferromagnetic Potts model. We use these methods to derive improved lower bounds on $W$ for several lattices.