{ "id": "1412.1609", "version": "v1", "published": "2014-12-04T10:24:20.000Z", "updated": "2014-12-04T10:24:20.000Z", "title": "On the Minimum Size of Signed Sumsets in Elementary Abelian Groups", "authors": [ "Bela Bajnok", "Ryan Matzke" ], "categories": [ "math.NT" ], "abstract": "For a finite abelian group $G$ and positive integers $m$ and $h$, we let $$\\rho(G, m, h) = \\min \\{|hA| \\; : \\; A \\subseteq G, |A|=m\\}$$ and $$\\rho_{\\pm} (G, m, h) = \\min \\{|h_{\\pm} A| \\; : \\; A \\subseteq G, |A|=m\\},$$ where $hA$ and $h_{\\pm} A$ denote the $h$-fold sumset and the $h$-fold signed sumset of $A$, respectively. The study of $\\rho(G, m, h)$ has a 200-year-old history and is now known for all $G$, $m$, and $h$. In previous work we provided an upper bound for $\\rho_{\\pm} (G, m, h)$ that we believe is exact, and proved that $\\rho_{\\pm} (G, m, h)$ agrees with $\\rho (G, m, h)$ when $G$ is cyclic. Here we study $\\rho_{\\pm} (G, m, h)$ for elementary abelian groups $G$; in particular, we determine all values of $m$ for which $\\rho_{\\pm} (\\mathbb{Z}_p^2, m, 2)$ equals $\\rho (\\mathbb{Z}_p^2, m, 2)$ for a given prime $p$.", "revisions": [ { "version": "v1", "updated": "2014-12-04T10:24:20.000Z" } ], "analyses": { "keywords": [ "elementary abelian groups", "minimum size", "finite abelian group", "upper bound", "fold signed sumset" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1412.1609B" } } }