2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/152726Following the work with Jimbo and Miwa, we introduce a certain degeneration of the elliptic algebra $A_{q,p}(\widehat{sl_2})$ and its boson realization. We investigate its rational limit. The limit is the central extension of the Yangian double DY(sl_2) at level one. We give a new boson realization of it. Based on these algebras, we reformulate the Smirnov's form factor bootstrap approach to the sine-Gordon theory and the SU(2) invariant Thirring model. A conjectural integral formula for form factor in the sine-Gordon theory is derived.21 pages, LaTeX file, Talk given at the Nankai-CRM joint meeting on "Extended and Quantum Algebras and their Applications to Physics", Tianjin, China, August 19-24, 1996. To appear in the CRM series in mathematical physics, Springer VerlagHigh Energy Physics - TheoryQuantum Algebratext