{ "id": "math/0604578", "version": "v2", "published": "2006-04-26T20:47:01.000Z", "updated": "2007-06-04T15:25:59.000Z", "title": "Permutation representations on Schubert varieties", "authors": [ "Julianna S. Tymoczko" ], "comment": "20 pages, v2: minor revisions", "categories": [ "math.RT", "math.AG", "math.CO" ], "abstract": "This paper defines and studies permutation representations on the equivariant cohomology of Schubert varieties, as representations both over C and over C[t_1, t_2,...,t_n]. We show these group actions are the same as an action of simple transpositions studied geometrically by M. Brion, and give topological meaning to the divided difference operators studied by Berstein-Gelfand-Gelfand, Demazure, Kostant-Kumar, and others. We analyze these representations using the combinatorial approach to equivariant cohomology introduced by Goresky-Kottwitz-MacPherson. We find that each permutation representation on equivariant cohomology produces a representation on ordinary cohomology that is trivial, though the equivariant representation is not.", "revisions": [ { "version": "v2", "updated": "2007-06-04T15:25:59.000Z" } ], "analyses": { "subjects": [ "20C30", "05E10", "14M15", "55N91", "20F55" ], "keywords": [ "schubert varieties", "studies permutation representations", "equivariant cohomology produces", "equivariant representation", "group actions" ], "note": { "typesetting": "TeX", "pages": 20, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2006math......4578T" } } }