2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/97042The sequence of rings $H^n, n\ge 0,$ introduced in math.QA/0103190, controls categorification of the quantum sl(2) invariant of tangles. We prove that the center of $H^n$ is isomorphic to the cohomology ring of the (n,n) Springer variety and show that the braid group action in the derived category of $H^n$-modules descends to the Springer action of the symmetric group.20 pages, 7 figuresQuantum Algebra16S99text