{ "id": "1511.02888", "version": "v1", "published": "2015-11-09T21:15:04.000Z", "updated": "2015-11-09T21:15:04.000Z", "title": "Hodge Theory for Combinatorial Geometries", "authors": [ "Karim Adiprasito", "June Huh", "Eric Katz" ], "comment": "61 pages. Comments welcome!", "categories": [ "math.CO", "math.AG" ], "abstract": "We prove the hard Lefschetz theorem and the Hodge-Riemann relations for a commutative ring associated to an arbitrary matroid M. We use the Hodge-Riemann relations to resolve a conjecture of Heron, Rota, and Welsh that postulates the log-concavity of the coefficients of the characteristic polynomial of M. We furthermore conclude that the f-vector of the independence complex of a matroid forms a log-concave sequence, proving a conjecture of Mason and Welsh for general matroids.", "revisions": [ { "version": "v1", "updated": "2015-11-09T21:15:04.000Z" } ], "analyses": { "keywords": [ "combinatorial geometries", "hodge theory", "hodge-riemann relations", "hard lefschetz theorem", "matroid forms" ], "note": { "typesetting": "TeX", "pages": 61, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2015arXiv151102888A" } } }