Quiver varieties and Weyl group actions
For a finite graph of type \(ADE\) with set of vertices \(I\), \textit{H.~Nakajima} associated to \(\mathbf{v,w}\in\mathbb{N}^I\) a ``quiver variety'' \(\mathcal M(\mathbf{v,w})\) and constructed a Weyl group action on the cohomology of \(\sqcup_{\mathbf v}\mathcal M(\mathbf{v,w})\) using techniques of hyper-Kähler geometry [see Duke Math. J. 76, No. 2, 365-416 (1994; Zbl 0826.17026), Duke J. Math. 91, No. 3, 515-560 (1998)]. In the paper under review it is given an alternative construction of this Weyl group action, based not on hyper-Kähler geometry, but on techniques of intersection cohomology. This gives in fact a refinement of the Weyl group action.
scientific article; zbMATH DE number 1448497