2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/210728Switched (singular) systems become very common, which requires some revision of the conceptual basis of system theory.19 pages, 8 figures. The complete, initial version of a work submitted (in a much more contracted form) to a journal, with both scientific and pedagogical stresses. The given classification of dynamic equations is concerned with the system-theoretical concept of "input", and may be of interest even for a pure mathematicianExactly Solvable and Integrable SystemsChaotic Dynamicstext