Journal of Statistical Physics, Vol. 56, Nos. 3/4, 1989. p. 261-290.
For some lattice systems with an infinite number of ground states, it is shown that the pressure and the coexistence surfaces of several phases admit asymptotic expansions around T=0. In particular, it follows that the coexistence surfaces are differentiable at T=0, and at low temperatures the stable states are those with maximal residual entropy. The results are applied to construct the phase diagrams for several spin-1 models.