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arXiv 1302.4295math.COcs.CCmath.PR
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正则组合结构的概率存在性

Probabilistic existence of regular combinatorial structures

Greg Kuperberg, Shachar Lovett, Ron Peled

摘要:

我们证明了以前不知道存在的定期组合对象的存在。具体来说,对于广泛的基本参数,我们证明了非平凡的正交表,t-设计和t-明智的排列的存在。在所有情况下,对象的大小都是最佳的,直到多项式开销。存在的证明是概率性的。我们表明,一个随机选择的结构具有所需的属性与积极的,但很小的概率。我们的方法还允许给一个给定的大小的对象的数量上,这是适用于计算正交表,t-设计和定期超图的数量,而精确的估计。主要技术成分是一个特殊的局部中心极限定理适合格随机游动与许多步骤。

英文摘要:

We show the existence of regular combinatorial objects which previously were not known to exist. Specifically, for a wide range of the underlying parameters, we show the existence of non-trivial orthogonal arrays, t-designs, and t-wise permutations. In all cases, the sizes of the objects are optimal up to polynomial overhead. The proof of existence is probabilistic. We show that a randomly chosen structure has the required properties with positive yet tiny probability. Our method allows also to give rather precise estimates on the number of objects of a given size and this is applied to count the number of orthogonal arrays, t-designs and regular hypergraphs. The main technical ingredient is a special local central limit theorem for suitable lattice random walks with finitely many steps.

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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