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arXiv math/0608131math.NTmath.CO
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许多集合的和大于差

Many sets have more sums than differences

Greg Martin, Kevin O'Bryant

摘要:

由于加法是可交换的,而减法不是,因此有限集S的和集S+S倾向于小于差集S-S。然而,在本文中,我们证明了三种可能性中的每一种(|S+S|>| S-S|, |S+S| =| S-S|, |S+S| <|S-S|)对于{0,1,.,n-1}。我们还表明,|S+S| - |S-S|可以采取任何整数值,我们表明,遗漏的差异的预期数量是渐近6,而预期数量的失踪和渐近10。文中还给出了有关这些量分布的其它数据和图表。

英文摘要:

Since addition is commutative but subtraction is not, the sumset S+S of a finite set S is predisposed to be smaller than the difference set S-S. In this paper, however, we show that each of the three possibilities (|S+S|>|S-S|, |S+S|=|S-S|, |S+S|<|S-S|) occur for a positive proportion of the subsets of {0, 1, ..., n-1}. We also show that the difference |S+S| - |S-S| can take any integer value, and we show that the expected number of omitted differences is asymptotically 6 while the expected number of missing sums is asymptotically 10. Other data and conjectures on the distribution of these quantities are also given.

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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