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arXiv 0709.1176math.COmath.NT
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论公平零和

On equitable zero sums

Ernie Croot, Christian Elsholtz

摘要:

众所周知,任何至少N个整数的序列都包含一个和为0(mod N)的子序列。然而,具有这种性质的序列可能非常少(例如,如果初始序列只有N 1,那么只有一个子序列)。当序列的长度L长得多时,我们可能会期望有2^L/N的连续性具有此性质(假设连续性具有均匀分布的模N项和-0类得到约2^L/N的连续性);然而,很容易看出这实际上是错误的。尽管如此,我们能够证明,如果初始序列的长度至少为4 N,并且N是奇数,则存在长度为L > N的子序列,其具有至少2^L/N的连续性,其总和为0 mod N。

英文摘要:

It is well-known that any sequence of at least N integers contains a subsequence whose sum is 0 (mod N). However, there can be very few subsequences with this property (e.g. if the initial sequence is just N 1's, then there is only one subsequence). When the length L of the sequence is much longer, we might expect that there are 2^L/N subsequences with this property (imagine the subsequences have sum-of-terms uniformly distributed modulo N -- the 0 class gets about 2^L/N subsequences); however, it is easy to see that this is actually false. Nonetheless, we are able to prove that if the initial sequence has length at least 4N, and N is odd, then there is a subsequence of length L > N, having at least 2^L/N subsequences that sum to 0 mod N.

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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