2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/137618We establish a convenient necessary and sufficient condition for a multiaffine real polynomial to be stable, and use it to verify that the half-plane property holds for seven small matroids that resisted the efforts of Choe, Oxley, Sokal, and Wagner [5].Combinatorics05B35, 05A20, 05E99, 26C10text