2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/222060Within a large class of exact solutions of the Einstein equations describing a black hole embedded in a Friedmann universe it is shown that, under certain assumptions, only those with comoving Hawking-Hayward quasi-local mass are generic, in the sense that they are late-time attractors.9 pages, LaTex, to appear in Phys. Lett. BGeneral Relativity and Quantum Cosmologytext