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arXiv 1704.02472math.COmath.GR
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二面体群中的差基

Difference bases in dihedral groups

Taras Banakh, Volodymyr Gavrylkiv

摘要:

如果一个群$G$的一个子集$B$中的每个元素$g\in G$都可以写成某些元素$a,b\in B$的差$g=ab^{-1}$,则称之为$G$的差基。差分基$B\subset G$的最小基数$|B|$称为$G$的差分大小,并由$Δ[G]$表示。分数$ð[G]:=Δ[G]/{\sqrt{|G|}}$称为$G$的差异特征。证明了对于每个$n\in\mathbb N$,$2n$阶二面体群$D_{2n}$具有差分特征$\sqrt{2}\leð[D_{2n}]\leq\frac{48}{\sqrt{586}}\approx1.983$ .此外,如果$n\ge 2\cdot 10^{15}$,则$ð[D_{2n}]<\frac{4}{\sqrt{6}}\approx1.633$。并计算了基数为$\le80$的所有二面体群的差的大小和特征。

英文摘要:

A subset $B$ of a group $G$ is called a difference basis of $G$ if each element $g\in G$ can be written as the difference $g=ab^{-1}$ of some elements $a,b\in B$. The smallest cardinality $|B|$ of a difference basis $B\subset G$ is called the difference size of $G$ and is denoted by $Δ[G]$. The fraction $ð[G]:=Δ[G]/{\sqrt{|G|}}$ is called the difference characteristic of $G$. We prove that for every $n\in\mathbb N$ the dihedral group $D_{2n}$ of order $2n$ has the difference characteristic $\sqrt{2}\leð[D_{2n}]\leq\frac{48}{\sqrt{586}}\approx1.983$. Moreover, if $n\ge 2\cdot 10^{15}$, then $ð[D_{2n}]<\frac{4}{\sqrt{6}}\approx1.633$. Also we calculate the difference sizes and characteristics of all dihedral groups of cardinality $\le80$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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