2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/73852The paper contains a simple proof of the classical Hahn decomposition theorem for charges and, as a corollary, an explicit measurable in parameter construction of a Radon-Nikodym derivative of one measure by another.Classical Analysis and ODEs28A99Hahn decomposition and Radon-Nikodym theorem with a parametertext