2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/220108In this talk I review three topics: (i) Heterotic strings from N=1 gauge theories; (ii) Planar equivalence and emergent center symmetry in QCD-like theories; (iii) Exact result for gluon scattering amplitudes in N=4 (dual conformality).20 pages, 3 figures; Invited Talk at PLANCK 2008, Barcelona, Spain, 19-23 May, 2008High Energy Physics - TheoryHigh Energy Physics - PhenomenologyMathematical Physicstext