{ "id": "1304.0949", "version": "v3", "published": "2013-04-03T13:30:41.000Z", "updated": "2014-03-27T14:06:19.000Z", "title": "Extremal set theory, cubic forms on $\\mathbb{F}_2^n$ and Hurwitz square identities", "authors": [ "Sophie Morier-Genoud", "Valentin Ovsienko" ], "categories": [ "math.CO", "math.NT" ], "abstract": "We consider a family, $\\mathcal{F}$, of subsets of an $n$-set such that the cardinality of the symmetric difference of any two elements $F,F'\\in\\mathcal{F}$ is not a multiple of 4. We prove that the maximal size of $\\mathcal{F}$ is bounded by $2n$, unless $n\\equiv{}3\\mod4$ when it is bounded by $2n+2$. Our method uses cubic forms on $\\mathbb{F}_2^n$ and the Hurwitz-Radon theory of square identities. We also apply this theory to obtain some information about boolean cubic forms and so-called additive quadruples.", "revisions": [ { "version": "v3", "updated": "2014-03-27T14:06:19.000Z" } ], "analyses": { "subjects": [ "05D05", "11B30", "11E25", "17A99" ], "keywords": [ "extremal set theory", "hurwitz square identities", "boolean cubic forms", "symmetric difference", "hurwitz-radon theory" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1304.0949M" } } }