2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/61673A notion of detectability for nonlinear systems is discussed. Within the framework of ``input to state stability'' (ISS), a dual notion of ``output to state stability'' (OSS), and a more complete detectability notion, ``input-output to state stability'' (IOSS) have appeared in the literature. This note addresses a variant of the IOSS property, using an integral norm to measure signals, as opposed to the standard supremum norm that appears in ISS theory.18 pages, no figuresOptimization and Control93D30; 93C10text