2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/152842We prove that if A is the basin of immediate attraction to a periodic attracting or parabolic point for a rational map f on the Riemann sphere, then periodic points in the boundary of A are dense in this boundary. To prove this in the non simply- connected or parabolic situations we prove a more abstract, geometric coding trees version.Dynamical Systemstext