2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/81957We present a new method that accurately approximates the shell-model ground-state by products of suitable states. The optimal factors are determined by a variational principle and result from the solution of rather low-dimensional eigenvalue problems. The power of this method is demonstrated by computations of ground-states and low-lying excitations in sd-shell and pf-shell nuclei.5+epsilon pages, 5 eps-figures. Main additions: wave-function overlaps, angular momentum expectation values, application to Ni56. To be published as Rapid Communication in PRCNuclear TheoryCondensed Mattertext