2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/126618Thermodynamic stable interaction pair potentials which are not of the form ``positive function + real continuous function of positive type'' are presented in dimension one. Construction of such a potential in dimension two is sketched. These constructions use only elementary calculations. The mathematical background is discussed separately.8 pagesMathematical Physics82B05; 52A07; 20K99text