2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/70078The main topic of this paper is various "hyperbolic" generalizations of the Edmonds-Rado theorem on the rank of intersection of two matroids. We prove several results in this direction and pose a few questions. We also give generalizations of the Obreschkoff theorem and recent results of J. Borcea and B. Shapiro.20 pagesCombinatoricsOptimization and Controltext