2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/109938We describe the ``action-angle'' integrable system underlying the structure of double-extremal black holes. This implies the existence of a canonical transformation from BPS to non-BPS black holes. We give examples of such canonical transformation for STU and for E(7(7))-invariant black holes12 pagesHigh Energy Physics - Theorytext