2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/149528A level-0 action of $U_q(\widehat{sl}_2)$ is defined on the sum of level-1 irreducible highest weight modules. With the aid of the affine Hecke algebras, this action is realized on the basis created by the vertex operators. This is a $q$-analogue of the Yangian symmetry in conformal field theory.24 pages, LaTeX 2.09 or LaTeX2e (and preferably amsfonts). Contribution to the Proceedings of the meeting `Statistical Mechanics and Quantum Field Theory', USC, May 16-21, 1994. (1st revision: Some technical changes regarding the completions and other minor corrections have been made.) (new revision: corrections in section 4.2)Quantum AlgebraHigh Energy Physics - Theorytext