{ "id": "1004.2685", "version": "v2", "published": "2010-04-15T18:35:01.000Z", "updated": "2011-01-03T21:08:14.000Z", "title": "A quasisymmetric function generalization of the chromatic symmetric function", "authors": [ "Brandon Humpert" ], "comment": "14 pages, 5 figures", "categories": [ "math.CO" ], "abstract": "The chromatic symmetric function $X_G$ of a graph $G$ was introduced by Stanley. In this paper we introduce a quasisymmetric generalization $X^k_G$ called the $k$-chromatic quasisymmetric function of $G$ and show that it is positive in the fundamental basis for the quasisymmetric functions. Following the specialization of $X_G$ to $\\chi_G(\\lambda)$, the chromatic polynomial, we also define a generalization $\\chi^k_G(\\lambda)$ and show that evaluations of this polynomial for negative values generalize a theorem of Stanley relating acyclic orientations to the chromatic polynomial.", "revisions": [ { "version": "v2", "updated": "2011-01-03T21:08:14.000Z" } ], "analyses": { "keywords": [ "chromatic symmetric function", "quasisymmetric function generalization", "chromatic polynomial", "chromatic quasisymmetric function", "stanley relating acyclic orientations" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1004.2685H" } } }