Towards Deterministic Algorithms for Constant-Depth Factors of Constant-Depth Circuits

Fuente: arXiv
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Main Authors: Kumar, Mrinal, Ramanathan, Varun, Saptharishi, Ramprasad, Volk, Ben Lee
Format: Preprint
Published: 2024
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author Kumar, Mrinal
Ramanathan, Varun
Saptharishi, Ramprasad
Volk, Ben Lee
author_facet Kumar, Mrinal
Ramanathan, Varun
Saptharishi, Ramprasad
Volk, Ben Lee
contents We design a deterministic subexponential time algorithm that takes as input a multivariate polynomial $f$ computed by a constant-depth circuit over rational numbers, and outputs a list $L$ of circuits (of unbounded depth and possibly with division gates) that contains all irreducible factors of $f$ computable by constant-depth circuits. This list $L$ might also include circuits that are spurious: they either do not correspond to factors of $f$ or are not even well-defined, e.g. the input to a division gate is a sub-circuit that computes the identically zero polynomial. The key technical ingredient of our algorithm is a notion of the pseudo-resultant of $f$ and a factor $g$, which serves as a proxy for the resultant of $g$ and $f/g$, with the advantage that the circuit complexity of the pseudo-resultant is comparable to that of the circuit complexity of $f$ and $g$. This notion, which might be of independent interest, together with the recent results of Limaye, Srinivasan and Tavenas, helps us derandomize one key step of multivariate polynomial factorization algorithms - that of deterministically finding a good starting point for Newton Iteration for the case when the input polynomial as well as the irreducible factor of interest have small constant-depth circuits.
format Preprint
id arxiv_https___arxiv_org_abs_2403_01965
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Towards Deterministic Algorithms for Constant-Depth Factors of Constant-Depth Circuits
Kumar, Mrinal
Ramanathan, Varun
Saptharishi, Ramprasad
Volk, Ben Lee
Computational Complexity
Data Structures and Algorithms
We design a deterministic subexponential time algorithm that takes as input a multivariate polynomial $f$ computed by a constant-depth circuit over rational numbers, and outputs a list $L$ of circuits (of unbounded depth and possibly with division gates) that contains all irreducible factors of $f$ computable by constant-depth circuits. This list $L$ might also include circuits that are spurious: they either do not correspond to factors of $f$ or are not even well-defined, e.g. the input to a division gate is a sub-circuit that computes the identically zero polynomial. The key technical ingredient of our algorithm is a notion of the pseudo-resultant of $f$ and a factor $g$, which serves as a proxy for the resultant of $g$ and $f/g$, with the advantage that the circuit complexity of the pseudo-resultant is comparable to that of the circuit complexity of $f$ and $g$. This notion, which might be of independent interest, together with the recent results of Limaye, Srinivasan and Tavenas, helps us derandomize one key step of multivariate polynomial factorization algorithms - that of deterministically finding a good starting point for Newton Iteration for the case when the input polynomial as well as the irreducible factor of interest have small constant-depth circuits.
title Towards Deterministic Algorithms for Constant-Depth Factors of Constant-Depth Circuits
topic Computational Complexity
Data Structures and Algorithms
url https://arxiv.org/abs/2403.01965