Key points are not available for this paper at this time.
It is shown that the two-dimensional q-component Potts model is equivalent to a staggered ice-type model. It is deduced that the model has a first-order phase transition for q>4, and a higher-order transition for q<or=4. The free energy and latent heat at the transition are calculated.
R. J. Baxter (Tue,) studied this question.