2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/149125The Kyoto group (Jimbo, Miwa, Nakayashikiet al.) showed that the partition function and correlation funtions of the eight-vertex model in antiferromagnetic phases can be calculated using simple analytical properties of the $R$-matrix. We extend these methods to ferromagnetic and disordered phases. We use Baxter's symmetries to obtain appropriate parametrizations of the $R$-matrix and to substantiate the validity of the analytical approach for these phases. These symmetries allow one to relate correlation functions in different phases.16 pages, a new section inserted instead of Eq. (4.15)High Energy Physics - Theorytext