{ "id": "1101.4492", "version": "v1", "published": "2011-01-24T10:43:37.000Z", "updated": "2011-01-24T10:43:37.000Z", "title": "On the number of subsequences with a given sum in a finite abelian group", "authors": [ "Gerard Jennhwa Chang", "Sheng-Hua Chen", "Yongke Qu", "Guoqing Wang", "Haiyan Zhang" ], "comment": "9 pages", "categories": [ "math.CO", "math.NT" ], "abstract": "Suppose $G$ is a finite abelian group and $S$ is a sequence of elements in $G$. For any element $g$ of $G$, let $N_g(S)$ denote the number of subsequences of $S$ with sum $g$. The purpose of this paper is to investigate the lower bound for $N_g(S)$. In particular, we prove that either $N_g(S)=0$ or $N_g(S) \\ge 2^{|S|-D(G)+1}$, where $D(G)$ is the smallest positive integer $\\ell$ such that every sequence over $G$ of length at least $\\ell$ has a nonempty zero-sum subsequence. We also characterize the structures of the extremal sequences for which the equality holds for some groups.", "revisions": [ { "version": "v1", "updated": "2011-01-24T10:43:37.000Z" } ], "analyses": { "keywords": [ "finite abelian group", "nonempty zero-sum subsequence", "smallest positive integer", "equality holds", "extremal sequences" ], "note": { "typesetting": "TeX", "pages": 9, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2011arXiv1101.4492J" } } }