License: Creative Commons Attribution 4.0 International license (CC BY 4.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.MFCS.2023.14
URN: urn:nbn:de:0030-drops-185480
URL: http://dagstuhl.sunsite.rwth-aachen.de/volltexte/2023/18548/
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Arvind, Vikraman ; Joglekar, Pushkar S.

Multivariate to Bivariate Reduction for Noncommutative Polynomial Factorization

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LIPIcs-MFCS-2023-14.pdf (0.6 MB)

Abstract

Based on a theorem of Bergman [Cohn, 2006] we show that multivariate noncommutative polynomial factorization is deterministic polynomial-time reducible to the factorization of bivariate noncommutative polynomials. More precisely, we show the following:
1) In the white-box setting, given an n-variate noncommutative polynomial f ∈ ?⟨X⟩ over a field ? (either a finite field or the rationals) as an arithmetic circuit (or algebraic branching program), computing a complete factorization of f into irreducible factors is deterministic polynomial-time reducible to white-box factorization of a noncommutative bivariate polynomial g ∈ ?⟨x,y⟩; the reduction transforms f into a circuit for g (resp. ABP for g), and given a complete factorization of g (namely, arithmetic circuits (resp. ABPs) for irreducible factors of g) the reduction recovers a complete factorization of f in polynomial time.
We also obtain a similar deterministic polynomial-time reduction in the black-box setting.
2) Additionally, we show over the field of rationals that bivariate linear matrix factorization of 4× 4 matrices is at least as hard as factoring square-free integers. This indicates that reducing noncommutative polynomial factorization to linear matrix factorization (as done in [Vikraman Arvind and Pushkar S. Joglekar, 2022]) is unlikely to succeed over the field of rationals even in the bivariate case. In contrast, multivariate linear matrix factorization for 3×3 matrices over rationals is in polynomial time.

BibTeX - Entry

@InProceedings{arvind_et_al:LIPIcs.MFCS.2023.14,
  author =	{Arvind, Vikraman and Joglekar, Pushkar S.},
  title =	{{Multivariate to Bivariate Reduction for Noncommutative Polynomial Factorization}},
  booktitle =	{48th International Symposium on Mathematical Foundations of Computer Science (MFCS 2023)},
  pages =	{14:1--14:15},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-292-1},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{272},
  editor =	{Leroux, J\'{e}r\^{o}me and Lombardy, Sylvain and Peleg, David},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/opus/volltexte/2023/18548},
  URN =		{urn:nbn:de:0030-drops-185480},
  doi =		{10.4230/LIPIcs.MFCS.2023.14},
  annote =	{Keywords: Arithmetic circuits, algebraic branching programs, polynomial factorization, automata, noncommutative polynomial ring}
}

Keywords: Arithmetic circuits, algebraic branching programs, polynomial factorization, automata, noncommutative polynomial ring
Collection: 48th International Symposium on Mathematical Foundations of Computer Science (MFCS 2023)
Issue Date: 2023
Date of publication: 21.08.2023

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