2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/112752We introduce an integral form U of the quantized enveloping algebra of sl_2. The algebra U is just large enough so that the quasi-R-matrix is contained in a completion of U\otimes U. We study several completions of the algebra U, and determine their centers. This study is motivated by a study of integrality properties of the quantum sl_2 invariants of links and integral homology spheres.31 pagesQuantum Algebra17B37; 57M27text