{ "id": "1002.1492", "version": "v1", "published": "2010-02-07T21:40:50.000Z", "updated": "2010-02-07T21:40:50.000Z", "title": "Books vs Triangles", "authors": [ "Dhruv Mubayi" ], "categories": [ "math.CO" ], "abstract": "A book of size b in a graph is an edge that lies in b triangles. Consider a graph G with n vertices and \\lfloor n^2/4\\rfloor +1 edges. Rademacher proved that G contains at least \\lfloor n/2\\rfloor triangles, and Erdos conjectured and Edwards proved that G contains a book of size at least n/6. We prove the following \"linear combination\" of these two results. Suppose that \\alpha\\in (1/2, 1) and the maximum size of a book in G is less than \\alpha n/2. Then G contains at least \\alpha(1-\\alpha) n^2/4 - o(n^2) triangles as n approaches infinity. This is asymptotically sharp. On the other hand, for every \\alpha\\in (1/3, 1/2), there exists \\beta>0 such that G contains at least \\beta n^3 triangles. It remains an open problem to determine the largest possible \\beta in terms of \\alpha. Our proof uses the Ruzsa-Szemeredi theorem.", "revisions": [ { "version": "v1", "updated": "2010-02-07T21:40:50.000Z" } ], "analyses": { "keywords": [ "linear combination", "approaches infinity", "open problem", "ruzsa-szemeredi theorem", "asymptotically sharp" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1002.1492M" } } }