2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/50605This is a summary of progress made in understanding the occurrence and properties of local, conserved, commuting charges in non-linear sigma-models, including principal chiral models (PCMs) and WZW models. (Contribution to the NATO-ASI meeting: Integrable Hierarchies and Modern Physical Theories, University of Illinois at Chicago, July 2000.)2 pages; plain TeXHigh Energy Physics - TheoryMathematical PhysicsExactly Solvable and Integrable Systemstext