Pseudorandom generators for combinatorial shapes
Pseudorandom generators for combinatorial shapes
复制标题
组合形状的伪随机生成器
DOI:
10.1145/1993636.1993671
复制
发表时间:
2011
期刊:
影响因子:
--
通讯作者:
David Zuckerman
中科院分区:
文献类型:
--
作者:
Parikshit Gopalan;Raghu Meka;Omer Reingold;David Zuckerman
We construct pseudorandom generators for <i>combinatorial shapes</i>, which substantially generalize combinatorial rectangles, ε-biased spaces, 0/1 halfspaces, and 0/1 modular sums. A function f:[m]<sup>n</sup> -> {0,1} is an (m,n)-combinatorial shape if there exist sets A<sub>1</sub>,...,A<sub>n</sub> ⊆ [m] and a symmetric function h:{0,1}<sup>n</sup> -> {0,1} such that f(x<sub>1</sub>,...,x<sub>n</sub>) = h(1<sub>A<sub>1</sub></sub>(x<sub>1</sub>),...,1<sub>A<sub>n</sub></sub>(x<sub>n</sub>)). Our generator uses seed length O(log m + log n + log<sup>2</sup>(1/ε)) to get error ε. When m = 2, this gives the first generator of seed length O(log n) which fools all weight-based tests, meaning that the distribution of the weight of any subset is ε-close to the appropriate binomial distribution in statistical distance. For our proof we give a simple lemma which allows us to convert closeness in Kolmogorov (cdf) distance to closeness in statistical distance. As a corollary of our technique, we give an alternative proof of a powerful variant of the classical central limit theorem showing convergence in statistical distance, instead of the usual Kolmogorov distance.