2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/50376These lectures are devoted to the low energy limit of \N2 SUSY gauge theories, which is described in terms of integrable systems. A special emphasis is on a duality that naturally acts on these integrable systems. The duality turns out to be an effective tool in constructing the double elliptic integrable system which describes the six-dimensional Seiberg-Witten theory. At the same time, it implies a series of relations between other Seiberg-Witten systems.27 pages, LaTeX (for Proceedings of the XXXIV PNPI Winter School); misprints and LaTeX errors are correctedHigh Energy Physics - Theorytext