{ "id": "math/0301091", "version": "v4", "published": "2003-01-09T21:16:42.000Z", "updated": "2004-10-20T13:49:51.000Z", "title": "Matsuki correspondence for the affine Grassmannian", "authors": [ "David Nadler" ], "comment": "28 pages; final version, to appear in Duke Math J", "categories": [ "math.AG", "math.RT" ], "abstract": "We present a version of the Matsuki correspondence for the affine Grassmannian $Gr=G(C((t)))/G(C[[t]])$ of a connected reductive complex algebraic group $G$. The main statement is an anti-isomorphism between the orbit posets of two subgroups of $G(C((t)))$ acting on $Gr$. The first is the polynomial loop group $LG_R$ of a real form $G_R$ of $G$; the second is the loop group $K(C((t)))$ of the complexification $K$ of a maximal compact subgroup $K_c$ of $G_R$. The orbit poset itself turns out to be simple to describe.", "revisions": [ { "version": "v4", "updated": "2004-10-20T13:49:51.000Z" } ], "analyses": { "keywords": [ "affine grassmannian", "matsuki correspondence", "orbit poset", "connected reductive complex algebraic group", "polynomial loop group" ], "note": { "typesetting": "TeX", "pages": 28, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2003math......1091N" } } }