License: Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.APPROX-RANDOM.2014.885
URN: urn:nbn:de:0030-drops-47456
URL: http://dagstuhl.sunsite.rwth-aachen.de/volltexte/2014/4745/
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Steinke, Thomas ; Vadhan, Salil ; Wan, Andrew

Pseudorandomness and Fourier Growth Bounds for Width-3 Branching Programs

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Abstract

We present an explicit pseudorandom generator for oblivious, read-once, width-3 branching programs, which can read their input bits in any order. The generator has seed length O~( log^3 n ).
The previously best known seed length for this model is n^{1/2+o(1)} due to Impagliazzo, Meka, and Zuckerman (FOCS'12). Our work generalizes a recent result of Reingold, Steinke, and Vadhan (RANDOM'13) for permutation branching programs. The main technical novelty underlying our generator is a new bound on the Fourier growth of width-3, oblivious, read-once branching programs. Specifically, we show that for any f : {0,1}^n -> {0,1} computed by such a branching program, and k in [n], sum_{|s|=k} |hat{f}(s)| < n^2 * (O(\log n))^k,
where f(x) = sum_s hat{f}(s) (-1)^<s,x> is the standard Fourier transform over Z_2^n. The base O(log n) of the Fourier growth is tight up to a factor of log log n.

BibTeX - Entry

@InProceedings{steinke_et_al:LIPIcs:2014:4745,
  author =	{Thomas Steinke and Salil Vadhan and Andrew Wan},
  title =	{{Pseudorandomness and Fourier Growth Bounds for Width-3 Branching Programs}},
  booktitle =	{Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2014)},
  pages =	{885--899},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-74-3},
  ISSN =	{1868-8969},
  year =	{2014},
  volume =	{28},
  editor =	{Klaus Jansen and Jos{\'e} D. P. Rolim and Nikhil R. Devanur and Cristopher Moore},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{http://drops.dagstuhl.de/opus/volltexte/2014/4745},
  URN =		{urn:nbn:de:0030-drops-47456},
  doi =		{10.4230/LIPIcs.APPROX-RANDOM.2014.885},
  annote =	{Keywords: Pseudorandomness, Branching Programs, Discrete Fourier Analysis}
}

Keywords: Pseudorandomness, Branching Programs, Discrete Fourier Analysis
Collection: Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2014)
Issue Date: 2014
Date of publication: 04.09.2014

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