Pseudorandom Generators from the Second Fourier Level and Applications to AC0 with Parity Gates

Authors Eshan Chattopadhyay, Pooya Hatami, Shachar Lovett, Avishay Tal

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Author Details

Eshan Chattopadhyay
  • Department of Computer Science, Cornell University, 107 Hoy Rd, Ithaca, NY, USA
Pooya Hatami
  • Department of Computer Science, University of Texas at Austin, 2317 Speedway, Austin, TX, USA
Shachar Lovett
  • Department of Computer Science, University of California San Diego, La Jolla, CA, USA
Avishay Tal
  • Department of Computer Science, Stanford University, 353 Serra Mall, Stanford, CA, USA

Cite AsGet BibTex

Eshan Chattopadhyay, Pooya Hatami, Shachar Lovett, and Avishay Tal. Pseudorandom Generators from the Second Fourier Level and Applications to AC0 with Parity Gates. In 10th Innovations in Theoretical Computer Science Conference (ITCS 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 124, pp. 22:1-22:15, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)


A recent work of Chattopadhyay et al. (CCC 2018) introduced a new framework for the design of pseudorandom generators for Boolean functions. It works under the assumption that the Fourier tails of the Boolean functions are uniformly bounded for all levels by an exponential function. In this work, we design an alternative pseudorandom generator that only requires bounds on the second level of the Fourier tails. It is based on a derandomization of the work of Raz and Tal (ECCC 2018) who used the above framework to obtain an oracle separation between BQP and PH. As an application, we give a concrete conjecture for bounds on the second level of the Fourier tails for low degree polynomials over the finite field F_2. If true, it would imply an efficient pseudorandom generator for AC^0[oplus], a well-known open problem in complexity theory. As a stepping stone towards resolving this conjecture, we prove such bounds for the first level of the Fourier tails.

Subject Classification

ACM Subject Classification
  • Theory of computation → Pseudorandomness and derandomization
  • Derandomization
  • Pseudorandom generator
  • Explicit construction
  • Random walk
  • Small-depth circuits with parity gates


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