{"title":"Difference bases in dihedral groups","authors":"T. Banakh, V. Gavrylkiv","doi":"10.22108/ijgt.2017.21612","DOIUrl":null,"url":null,"abstract":"A subset $B$ of a group $G$ is called a {em difference basis} of $G$ if each element $gin G$ can be written as the difference $g=ab^{-1}$ of some elements $a,bin B$. The smallest cardinality $|B|$ of a difference basis $Bsubset G$ is called the {em difference size} of $G$ and is denoted by $Delta[G]$. The fraction $eth[G]:=Delta[G]/{sqrt{|G|}}$ is called the {em difference characteristic} of $G$. We prove that for every $nin N$ the dihedral group $D_{2n}$ of order $2n$ has the difference characteristic $sqrt{2}leeth[D_{2n}]leqfrac{48}{sqrt{586}}approx1.983$. Moreover, if $nge 2cdot 10^{15}$, then $eth[D_{2n}]<frac{4}{sqrt{6}}approx1.633$. Also we calculate the difference sizes and characteristics of all dihedral groups of cardinality $le80$.","PeriodicalId":43007,"journal":{"name":"International Journal of Group Theory","volume":"8 1","pages":"43-50"},"PeriodicalIF":0.7000,"publicationDate":"2017-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Group Theory","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.22108/ijgt.2017.21612","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 1
Abstract
A subset $B$ of a group $G$ is called a {em difference basis} of $G$ if each element $gin G$ can be written as the difference $g=ab^{-1}$ of some elements $a,bin B$. The smallest cardinality $|B|$ of a difference basis $Bsubset G$ is called the {em difference size} of $G$ and is denoted by $Delta[G]$. The fraction $eth[G]:=Delta[G]/{sqrt{|G|}}$ is called the {em difference characteristic} of $G$. We prove that for every $nin N$ the dihedral group $D_{2n}$ of order $2n$ has the difference characteristic $sqrt{2}leeth[D_{2n}]leqfrac{48}{sqrt{586}}approx1.983$. Moreover, if $nge 2cdot 10^{15}$, then $eth[D_{2n}]
期刊介绍:
International Journal of Group Theory (IJGT) is an international mathematical journal founded in 2011. IJGT carries original research articles in the field of group theory, a branch of algebra. IJGT aims to reflect the latest developments in group theory and promote international academic exchanges.