{ "id": "1004.3709", "version": "v1", "published": "2010-04-21T13:53:15.000Z", "updated": "2010-04-21T13:53:15.000Z", "title": "Freiman homomorphisms of random subsets of $\\mathbb{Z}_{N}$", "authors": [ "Gonzalo Fiz Pontiveros" ], "categories": [ "math.CO" ], "abstract": "Let $A$ be a random subset of $\\mathbb{Z}_{N}$ obtained by including each element of $\\mathbb{Z}_{N}$ in $A$ independently with probability $p$. We say that $A$ is \\emph{linear} if the only Freiman homomorphisms are given by the restrictions of functions of the form $f(x)= ax+b$. For which values of $p$ do we have that $A$ is linear with high probability as $N\\to\\infty$ ? First, we establish a geometric characterisation of linear subsets. Second, we show that if $p=o(N^{-2/3})$ then $A$ is not linear with high probability whereas if $p=N^{-1/2+\\epsilon}$ for any $\\epsilon>0$ then $A$ is linear with high probability.", "revisions": [ { "version": "v1", "updated": "2010-04-21T13:53:15.000Z" } ], "analyses": { "keywords": [ "freiman homomorphisms", "random subset", "high probability", "geometric characterisation", "linear subsets" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1004.3709F" } } }