2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/54206The basic concepts underlying our analysis of {\it W-algebras} as extended symmetries of integrable systems are summarized. The construction starts from the second hamiltonian structure of ``Generalized Drinfel'd-Sokolov'' hierarchies, and its correspondence with the $A_1$-embeddings is established, providing a rather simple and general scheme.6 pages, LaTeX, Proceedings of the VIIIth J. A. Swieca Summer School (Rio de Janeiro, Brazil, February 1995)High Energy Physics - Theorytext