2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/34462We review here how Newton's law can be approximately recovered in the simple, "paradigmatic", case of a flat $Z_2$-symmetric brane in a 5-D anti-de Sitter bulk. We then comment on the difficulties encountered so far in extending this analysis to cosmological perturbations on a Robertson-Walker brane.11 pages, Tex, proceedings of the talk presented at the conference ERE 2002 held in Menorca in september 2002General Relativity and Quantum CosmologyAstrophysicsHigh Energy Physics - Theorytext