arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1402.5775math.COmath.NT
收藏

实数与复数的新的和积估计

New sum-product estimates for real and complex numbers

Antal Balog, Oliver Roche-Newton

摘要:

和积问题的一个变体试图表明,由加法和乘法运算定义的集合总是很大的。在本文中,我们证明了这种类型的新结果。特别是,我们表明,对于任何有限集$A$的正实数,这是真的,$$\left|\left\{\frac{a+b}{c+d}:a,b,c,d\in{A}\right\}\right|\geq{2|A|^2-1}.$$作为这个结果的后果,它也建立$$|4^{k-1}A^{(k)}|:=|\underbrace{\underbrace{A\cdots{A}}_\textrm{k times}+\cdots{+A\cdots{A}}}_\textrm{$4^{k-1}$ times}|\geq{|A|^k}.$$后来,它表明,这两个界限举行的情况下,当$A$是一个有限集的复数,虽然较小的乘法常数。

英文摘要:

A variation on the sum-product problem seeks to show that a set which is defined by additive and multiplicative operations will always be large. In this paper, we prove new results of this type. In particular, we show that for any finite set $A$ of positive real numbers, it is true that $$\left|\left\{\frac{a+b}{c+d}:a,b,c,d\in{A}\right\}\right|\geq{2|A|^2-1}.$$ As a consequence of this result, it is also established that $$|4^{k-1}A^{(k)}|:=|\underbrace{\underbrace{A\cdots{A}}_\textrm{k times}+\cdots{+A\cdots{A}}}_\textrm{$4^{k-1}$ times}|\geq{|A|^k}.$$ Later on, it is shown that both of these bounds hold in the case when $A$ is a finite set of complex numbers, although with smaller multiplicative constants.

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。

↑