From Fibonacci numbers to central limit type theorems
From Fibonacci numbers to central limit type theorems
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从斐波那契数到中心极限型定理
DOI:
10.1016/j.jcta.2012.03.014
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发表时间:
2010
期刊:
影响因子:
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通讯作者:
Yinghui Wang
中科院分区:
文献类型:
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作者:
Steven J. Miller;Yinghui Wang
A beautiful theorem of Zeckendorf states that every integer can be written uniquely as a sum of non-consecutive Fibonacci numbers [Formula: see text] . Lekkerkerker (1951–1952) [13] proved the average number of summands for integers in [Fn,Fn+1) is n/(φ2+1), with φ the golden mean. This has been generalized: given non-negative integers c1,c2,…,cLwith c1,cL>0 and recursive sequence [Formula: see text] with H1=1, Hn+1=c1Hn+c2Hn−1+⋯+cnH1+1 (1⩽n<L) and Hn+1=c1Hn+c2Hn−1+⋯+cLHn+1−L(n⩾L), every positive integer can be written uniquely as ∑aiHiunder natural constraints on the aiʼs, the mean and variance of the numbers of summands for integers in [Hn,Hn+1) are of size n, and as n→∞ the distribution of the number of summands converges to a Gaussian. Previous approaches used number theory or ergodic theory. We convert the problem to a combinatorial one. In addition to re-deriving these results, our method generalizes to other problems (in the sequel paper (Gaudet et al., preprint [2]) we show how this perspective allows us to determine the distribution of gaps between summands). For example, it is known that every integer can be written uniquely as a sum of the ±Fnʼs, such that every two terms of the same (opposite) sign differ in index by at least 4 (3). The presence of negative summands introduces complications and features not seen in previous problems. We prove that the distribution of the numbers of positive and negative summands converges to a bivariate normal with computable, negative correlation, namely −(21−2φ)/(29+2φ)≈−0.551058.