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arXiv 1305.0941math.NT
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关于均匀随机序列素分解的依赖量

On the Amount of Dependence in the Prime Factorization of a Uniform Random Integer

Richard Arratia

摘要:

从1到n均匀分布的随机整数的素因子分解有多少依赖性?把n个点的随机排列分解成圈,有多少依赖性?Poisson-Dirichlet过程和标度不变的泊松过程之间的关系是什么?对于全变差距离,只考虑小分量;对于Wasserstein距离,考虑所有分量,这三个问题的答案基本相同。Wasserstein距离是将依赖系统改变为独立系统所需的改变(插入和删除)的预期数量。特别地,我们证明了对于素数,粗略地说,2+o(1)的变化是必要的,并且足以将从1到n的均匀分布的随机整数转换为随机整数prod_{p leq n} p^{Z_p},其中因子p的重数Z_p是几何分布的,并且所有Z_p都是独立的。变化是,概率趋于1,一个缺失,连同随机数的插入,具有期望1+o(1)。证明2+ π满足的关键工具是素数多重性的无限独立模型与(0,infty)上的标度不变泊松过程的耦合。这个构造的一个推论是比林斯利1972年弱收敛结果中关于到Poisson-Dirichlet距离的第一个度量界。我们的界限采用以下形式:存在耦合,其中E和|log P_i(n)-(log n)V_i| = O(\log \log n),其中P_i表示第i个最大素因子,V_i表示Poisson-Dirichlet过程的第i个分量。这是合理的推测,O(1)是可实现的。

英文摘要:

How much dependence is there in the prime factorization of a random integer distributed uniformly from 1 to n? How much dependence is there in the decomposition into cycles of a random permutation of n points? What is the relation between the Poisson-Dirichlet process and the scale invariant Poisson process? These three questions have essentially the same answers, with respect to total variation distance, considering only small components, and with respect to a Wasserstein distance, considering all components. The Wasserstein distance is the expected number of changes -- insertions and deletions -- needed to change the dependent system into an independent system. In particular we show that for primes, roughly speaking, 2+o(1) changes are necessary and sufficient to convert a uniformly distributed random integer from 1 to n into a random integer prod_{p leq n} p^{Z_p} in which the multiplicity Z_p of the factor p is geometrically distributed, with all Z_p independent. The changes are, with probability tending to 1, one deletion, together with a random number of insertions, having expectation 1+o(1). The crucial tool for showing that 2+epsilon suffices is a coupling of the infinite independent model of prime multiplicities, with the scale invariant Poisson process on (0,infty). A corollary of this construction is the first metric bound on the distance to the Poisson-Dirichlet in Billingsley's 1972 weak convergence result. Our bound takes the form: there are couplings in which E sum |log P_i(n) - (log n) V_i | = O(\log \log n), where P_i denotes the i-th largest prime factor and V_i denotes the i-th component of the Poisson-Dirichlet process. It is reasonable to conjecture that O(1) is achievable.

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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