{ "id": "1904.01262", "version": "v1", "published": "2019-04-02T07:49:38.000Z", "updated": "2019-04-02T07:49:38.000Z", "title": "Combinatorial reciprocity for the chromatic polynomial and the chromatic symmetric function", "authors": [ "Olivier Bernardi", "Philippe Nadeau" ], "categories": [ "math.CO" ], "abstract": "Let G be a graph, and let $\\chi$G be its chromatic polynomial. For any non-negative integers i, j, we give an interpretation for the evaluation $\\chi$ (i) G (--j) in terms of acyclic orientations. This recovers the classical interpretations due to Stanley and to Green and Zaslavsky respectively in the cases i = 0 and j = 0. We also give symmetric function refinements of our interpretations, and some extensions. The proofs use heap theory in the spirit of a 1999 paper of Gessel.", "revisions": [ { "version": "v1", "updated": "2019-04-02T07:49:38.000Z" } ], "analyses": { "keywords": [ "chromatic symmetric function", "chromatic polynomial", "combinatorial reciprocity", "symmetric function refinements", "acyclic orientations" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }