{ "id": "0910.5026", "version": "v1", "published": "2009-10-27T01:46:50.000Z", "updated": "2009-10-27T01:46:50.000Z", "title": "On some partitions of an affine flag variety", "authors": [ "Xuhua He" ], "comment": "Preliminary version. Comments are welcome", "categories": [ "math.RT", "math.AG" ], "abstract": "In this paper, we discuss some partitions of affine flag varieties. These partitions include as special cases the partition of affine flag variety into affine Deligne-Lusztig varieties and the affine analogue of the partition of flag varieties into $\\cb_w(b)$ introduced by Lusztig in \\cite{L1} as part of the definition of character sheaves. Among other things, we give a formula for the dimension of affine Deligne-Lusztig varieties for classical loop groups in terms of degrees of class polynomials of extended affine Hecke algebra. We also prove that any simple $GL_n(\\FF_q((\\e)))$-module occurs as a subquotient of the cohomology of affine Deligne-Lusztig variety $X_w(1)$ for some $w$ in the extended affine Weyl group $\\ZZ^n \\rtimes S_n$ must occurs for some $w$ in the finite Weyl group $S_n$. Similar result holds for $Sp_{2n}$.", "revisions": [ { "version": "v1", "updated": "2009-10-27T01:46:50.000Z" } ], "analyses": { "keywords": [ "affine flag variety", "affine deligne-lusztig variety", "extended affine hecke algebra", "extended affine weyl group", "finite weyl group" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2009arXiv0910.5026H" } } }