{ "id": "1301.6796", "version": "v1", "published": "2013-01-28T22:14:20.000Z", "updated": "2013-01-28T22:14:20.000Z", "title": "Beyond alternating permutations: Pattern avoidance in Young diagrams and tableaux", "authors": [ "Nihal Gowravaram", "Ravi Jagadeesan" ], "comment": "49 pages; comments are welcomed", "categories": [ "math.CO" ], "abstract": "We investigate pattern avoidance in alternating permutations and generalizations thereof. First, we study pattern avoidance in an alternating analogue of Young diagrams. In particular, we extend Babson-West's notion of shape-Wilf equivalence to apply to alternating permutations and so generalize results of Backelin-West-Xin and Ouchterlony to alternating permutations. Second, we study pattern avoidance in the more general context of permutations with restricted ascents and descents. We consider a question of Lewis regarding permutations that are the reading words of thickened staircase Young tableaux, that is, permutations that have (k - 1) ascents followed by a descent, followed by (k - 1) ascents, et cetera. We determine the relative sizes of the sets of pattern-avoiding (k - 1)-ascent permutations in terms of the forbidden pattern. Furthermore, we give inequalities in the sizes of sets of pattern-avoiding permutations in this context that arise from further extensions of shape-equivalence type enumerations.", "revisions": [ { "version": "v1", "updated": "2013-01-28T22:14:20.000Z" } ], "analyses": { "subjects": [ "05A05", "05A19" ], "keywords": [ "alternating permutations", "young diagrams", "study pattern avoidance", "shape-equivalence type enumerations", "extend babson-wests notion" ], "note": { "typesetting": "TeX", "pages": 49, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1301.6796G" } } }