%0 Journal Article %T Kazhdan-Lusztig basis and a geometric filtration of an affine Hecke algebra %A Toshiyuki Tanisaki %A Nanhua Xi %J Mathematics %D 2004 %I arXiv %X According to Kazhdan-Lusztig and Ginzburg, the Hecke algebra of an affine Weyl group is identified with the equivariant $K$-group of Steinberg's triple variety. The $K$-group is equipped with a filtration indexed by closed $G$-stable subvarieties of the nilpotent variety, where $G$ is the corresponding reductive algebraic group over $\mathbb{C}$. In this paper we will show in the case of type $A$ that the filtration is compatible with the Kazhdan-Lusztig basis of the Hecke algebra. %U http://arxiv.org/abs/math/0411304v1