A near-optimal Quadratic Goldreich-Levin algorithm

Fuente: arXiv
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Autori principali: Briët, Jop, Castro-Silva, Davi
Natura: Preprint
Pubblicazione: 2025
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author Briët, Jop
Castro-Silva, Davi
author_facet Briët, Jop
Castro-Silva, Davi
contents In this paper, we give a quadratic Goldreich-Levin algorithm that is close to optimal in the following ways. Given a bounded function $f$ on the Boolean hypercube $\mathbb{F}_2^n$ and any $\varepsilon>0$, the algorithm returns a quadratic polynomial $q: \mathbb{F}_2^n \to \mathbb{F}_2$ so that the correlation of $f$ with the function $(-1)^q$ is within an additive $\varepsilon$ of the maximum possible correlation with a quadratic phase function. The algorithm runs in $O_\varepsilon(n^3)$ time and makes $O_\varepsilon(n^2\log n)$ queries to $f$, which matches the information-theoretic lower bound of $Ω(n^2)$ queries up to a logarithmic factor. As a result, we obtain a number of corollaries: - A near-optimal self-corrector of quadratic Reed-Muller codes, which makes $O_\varepsilon(n^2\log n)$ queries to a Boolean function $f$ and returns a quadratic polynomial $q$ whose relative Hamming distance to $f$ is within $\varepsilon$ of the minimum distance. - An algorithmic polynomial inverse theorem for the order-3 Gowers uniformity norm. - An algorithm that makes a polynomial number of queries to a bounded function $f$ and decomposes $f$ as a sum of poly$(1/\varepsilon)$ quadratic phase functions and error terms of order $\varepsilon$. Our algorithm is obtained using ideas from recent work on quantum learning theory. Its construction deviates from previous approaches based on algorithmic proofs of the inverse theorem for the order-3 uniformity norm (and in particular does not rely on the recent resolution of the polynomial Fre\uıman-Ruzsa conjecture).
format Preprint
id arxiv_https___arxiv_org_abs_2505_13134
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A near-optimal Quadratic Goldreich-Levin algorithm
Briët, Jop
Castro-Silva, Davi
Computational Complexity
Combinatorics
In this paper, we give a quadratic Goldreich-Levin algorithm that is close to optimal in the following ways. Given a bounded function $f$ on the Boolean hypercube $\mathbb{F}_2^n$ and any $\varepsilon>0$, the algorithm returns a quadratic polynomial $q: \mathbb{F}_2^n \to \mathbb{F}_2$ so that the correlation of $f$ with the function $(-1)^q$ is within an additive $\varepsilon$ of the maximum possible correlation with a quadratic phase function. The algorithm runs in $O_\varepsilon(n^3)$ time and makes $O_\varepsilon(n^2\log n)$ queries to $f$, which matches the information-theoretic lower bound of $Ω(n^2)$ queries up to a logarithmic factor. As a result, we obtain a number of corollaries: - A near-optimal self-corrector of quadratic Reed-Muller codes, which makes $O_\varepsilon(n^2\log n)$ queries to a Boolean function $f$ and returns a quadratic polynomial $q$ whose relative Hamming distance to $f$ is within $\varepsilon$ of the minimum distance. - An algorithmic polynomial inverse theorem for the order-3 Gowers uniformity norm. - An algorithm that makes a polynomial number of queries to a bounded function $f$ and decomposes $f$ as a sum of poly$(1/\varepsilon)$ quadratic phase functions and error terms of order $\varepsilon$. Our algorithm is obtained using ideas from recent work on quantum learning theory. Its construction deviates from previous approaches based on algorithmic proofs of the inverse theorem for the order-3 uniformity norm (and in particular does not rely on the recent resolution of the polynomial Fre\uıman-Ruzsa conjecture).
title A near-optimal Quadratic Goldreich-Levin algorithm
topic Computational Complexity
Combinatorics
url https://arxiv.org/abs/2505.13134