{ "id": "0704.3067", "version": "v1", "published": "2007-04-23T22:06:24.000Z", "updated": "2007-04-23T22:06:24.000Z", "title": "Kazhdan--Lusztig polynomials for maximally-clustered hexagon-avoiding permutations", "authors": [ "Brant C. Jones" ], "comment": "18 pages", "categories": [ "math.CO", "math.RT" ], "abstract": "We provide a non-recursive description for the bounded admissible sets of masks used by Deodhar's algorithm to calculate the Kazhdan--Lusztig polynomials $P_{x,w}(q)$ of type $A$, in the case when $w$ is hexagon avoiding and maximally clustered. This yields a combinatorial description of the Kazhdan--Lusztig basis elements of the Hecke algebra associated to such permutations $w$. The maximally-clustered hexagon-avoiding elements are characterized by avoiding the seven classical permutation patterns $\\{3421, 4312, 4321, 46718235, 46781235, 56718234, 56781234\\}$. We also briefly discuss the application of heaps to permutation pattern characterization.", "revisions": [ { "version": "v1", "updated": "2007-04-23T22:06:24.000Z" } ], "analyses": { "subjects": [ "20C08" ], "keywords": [ "kazhdan-lusztig polynomials", "maximally-clustered hexagon-avoiding permutations", "seven classical permutation patterns", "kazhdan-lusztig basis elements", "permutation pattern characterization" ], "note": { "typesetting": "TeX", "pages": 18, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2007arXiv0704.3067J" } } }