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arXiv 0806.0092math.NTmath.CO
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子集和的渐近紧界

Asymptotically tight bounds on subset sums

Simon Griffiths

摘要:

对于有限阿贝尔群G的子集A,定义Sigma(A)={ sum_{a\in B} a:B \subset A}.在Sigma(A)具有平凡稳定子的情况下,可以推导出Sigma(A)的大小在|A|中至少是二次的;|西格玛(A)|>= |A| ^{2}/64最近由De Vos、Goddyn、Mohar和Samal获得。我们将这个界改进到渐近最好的可能结果|西格玛(A)|>=(1/4-o(1))|A| ^{2}。我们还研究了一个相关的问题,其中A是任何子集的Z_{n}与所有元素互质的A的n;它最近已被证明,由Vu,如果这样的一个集合A的性质西格玛(A)是不是Z_{n}然后|A| =O(sqrt{n})。De Vos,Goddyn,Mohar和Samal将此界改进为|A| <= 8 sqrt {n},我们进一步改进此界,得到渐近最佳可能结果|A| <=(2+o(1))sqrt{n}.

英文摘要:

For a subset A of a finite abelian group G we define Sigma(A)={sum_{a\in B}a:B\subset A}. In the case that Sigma(A) has trivial stabiliser, one may deduce that the size of Sigma(A) is at least quadratic in |A|; the bound |Sigma(A)|>= |A|^{2}/64 has recently been obtained by De Vos, Goddyn, Mohar and Samal. We improve this bound to the asymptotically best possible result |Sigma(A)|>= (1/4-o(1))|A|^{2}. We also study a related problem in which A is any subset of Z_{n} with all elements of A coprime to n; it has recently been shown, by Vu, that if such a set A has the property Sigma(A) is not Z_{n} then |A|=O(sqrt{n}). This bound was improved to |A|<= 8sqrt{n} by De Vos, Goddyn, Mohar and Samal, we further improve the bound to the asymptotically best possible result |A|<= (2+o(1))sqrt{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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