2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/186606We present simple string models which dynamically break supersymmetry without non-Abelian gauge dynamics. The Fayet model, the Polonyi model, and the O'Raifeartaigh model each arise from D-branes at a specific type of singularity. D-brane instanton effects generate the requisite exponentially small scale of supersymmetry breaking.12 pages, 6 figures, harvmac. v2: minor correctionsHigh Energy Physics - Theorytext