2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/55136Exact solutions to the low-energy effective action of the four-dimensional, N=2 supersymmetric gauge theories with matter (including N=2 super-QCD) are discussed from the three different viewpoints: (i) instanton calculus, (ii) N=2 harmonic superspace, and (iii) M theory. The emphasis is made on the foundations of all three approaches and their relationship.45 pages, LaTeX, 6 figures, macros included; a few references added, conclusion expandedHigh Energy Physics - Theorytext