2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/28992The occurrence of mesoscopic fluctuations in statistical systems implies, from the point of view of dynamical theory, the existence of local instabilities. However, the presence of such fluctuations can make a system, as a whole, more stable from the thermodynamic point of view. Thus, in many cases, a local dynamic instability is a requisite for the global thermodynamic stability. This idea is illustrated by several spin models.1 file, 23 pages, LaTex, no figuresStatistical Mechanicstext