2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/54218Many two-dimensional classical field theories have hidden symmetries that form an infinite-dimensional algebra. For those examples that correspond to effective descriptions of compactified superstring theories, the duality group is expected to be a large discrete subgroup of the hidden symmetry group. With this motivation, we explore the hidden symmetries of principal chiral models and symmetric space models.14 pages, latexHigh Energy Physics - Theorytext