2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/142850This is a straightforward introduction to the properties of polynomials in many variables that do not vanish in the open upper half plane. Such polynomials generalize many of the well-known properties of polynomials with all real roots.13 pagesClassical Analysis and ODEs26C10, 12D10, 30C15text