2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/113771In the paper a one-dimensional model with nearest - neighbor interactions $I_n, n\in \Z$ and spin values $\pm 1$ is considered. We describe a condition on parametres $I_n$ under which the phase transition occurs. In particular, we show that the phase transition occurs if $I_n\geq |n|, n\in \Z.$Published in Siberian Adv.Math. 2006, V.16, n.2, p.121-125Mathematical Physics82B20text