{ "id": "1702.06666", "version": "v1", "published": "2017-02-22T03:44:09.000Z", "updated": "2017-02-22T03:44:09.000Z", "title": "Gamma-positivity of variations of Eulerian polynomials", "authors": [ "John Shareshian", "Michelle L. Wachs" ], "comment": "29 pages", "categories": [ "math.CO" ], "abstract": "An identity of Chung, Graham and Knuth involving binomial coefficients and Eulerian numbers motivates our study of a class of polynomials that we call binomial-Eulerian polynomials. These polynomials share several properties with the Eulerian polynomials. For one thing, they are $h$-polynomials of simplicial polytopes, which gives a geometric interpretation of the fact that they are palindromic and unimodal. A formula of Foata and Sch\\\"utzenberger shows that the Eulerian polynomials have a stronger property, namely $\\gamma$-positivity, and a formula of Postnikov, Reiner and Williams does the same for the binomial-Eulerian polynomials. We obtain $q$-analogs of both the Foata-Sch\\\"utzenberger formula and an alternative to the Postnikov-Reiner-Williams formula, and we show that these $q$-analogs are specializations of analogous symmetric function identities. Algebro-geometric interpretations of these symmetric function analogs are presented.", "revisions": [ { "version": "v1", "updated": "2017-02-22T03:44:09.000Z" } ], "analyses": { "subjects": [ "05A05", "05E05", "05E10", "05E45", "52B05" ], "keywords": [ "gamma-positivity", "variations", "binomial-eulerian polynomials", "analogous symmetric function identities", "symmetric function analogs" ], "note": { "typesetting": "TeX", "pages": 29, "language": "en", "license": "arXiv", "status": "editable" } } }