{ "id": "1907.07639", "version": "v1", "published": "2019-07-17T16:53:55.000Z", "updated": "2019-07-17T16:53:55.000Z", "title": "A Tight Bound for Hyperaph Regularity", "authors": [ "Guy Moshkovitz", "Asaf Shapira" ], "comment": "To appear in GAFA. This is a merged version of arXiv:1804.05511 and arXiv:1804.05513. See arXiv:1804.05511 for a self contained proof of the theorem for the special case of 3-uniform hypergraphs", "categories": [ "math.CO" ], "abstract": "The hypergraph regularity lemma -- the extension of Szemer\\'edi's graph regularity lemma to the setting of $k$-uniform hypergraphs -- is one of the most celebrated combinatorial results obtained in the past decade. By now there are several (very different) proofs of this lemma, obtained by Gowers, by Nagle-R\\\"odl-Schacht-Skokan and by Tao. Unfortunately, what all these proofs have in common is that they yield regular partitions whose order is given by the $k$-th Ackermann function. We show that such Ackermann-type bounds are unavoidable for every $k \\ge 2$, thus confirming a prediction of Tao. Prior to our work, the only result of this type was Gowers' famous lower bound for graph regularity.", "revisions": [ { "version": "v1", "updated": "2019-07-17T16:53:55.000Z" } ], "analyses": { "keywords": [ "hyperaph regularity", "tight bound", "szemeredis graph regularity lemma", "yield regular partitions", "hypergraph regularity lemma" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }