{ "id": "1809.01259", "version": "v1", "published": "2018-09-04T22:32:24.000Z", "updated": "2018-09-04T22:32:24.000Z", "title": "Sidorenko's conjecture for blow-ups", "authors": [ "David Conlon", "Joonkyung Lee" ], "comment": "12 pages", "categories": [ "math.CO" ], "abstract": "A celebrated conjecture of Sidorenko and Erd\\H{o}s-Simonovits states that, for all bipartite graphs $H$, quasirandom graphs contain asymptotically the minimum number of copies of $H$ taken over all graphs with the same order and edge density. This conjecture has attracted considerable interest over the last decade and is now known to hold for a broad range of bipartite graphs, with the overall trend saying that a graph satisfies the conjecture if it can be built from simple building blocks such as trees in a certain recursive fashion. Our contribution here, which goes beyond this paradigm, is to show that the conjecture holds for any bipartite graph $H$ with bipartition $A \\cup B$ where there are many vertices in $B$ whose degree equals the maximum degree. As a corollary, we have that for every bipartite graph $H$ with bipartition $A \\cup B$, there is a positive integer $p$ such that the blow-up $H_A^p$ formed by taking $p$ vertex-disjoint copies of $H$ and gluing all copies of $A$ along corresponding vertices satisfies the conjecture. Another way of viewing this latter result is that for every bipartite $H$ there is a positive integer $p$ such that an $L^p$-version of Sidorenko's conjecture holds for $H$.", "revisions": [ { "version": "v1", "updated": "2018-09-04T22:32:24.000Z" } ], "analyses": { "keywords": [ "bipartite graph", "quasirandom graphs contain", "positive integer", "sidorenkos conjecture holds", "bipartition" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable" } } }