2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/19542In this note we explain the use of the cavity method directly at zero temperature, in the case of the spin glass on a Bethe lattice. The computation is done explicitly in the formalism equivalent to 'one step replica symmetry breaking'; we compute the energy of the global ground state, as well as the complexity of equilibrium states at a given energy. Full results are presented for a Bethe lattice with connectivity equal to three.22 pages, 8 figures; Some minor correctionsDisordered Systems and Neural Networkstext