English

Finite matrix multiplication algorithms from infinite groups

Group Theory 2025-08-20 v2 Data Structures and Algorithms

Abstract

The Cohn-Umans (FOCS '03) group-theoretic framework for matrix multiplication produces fast matrix multiplication algorithms from three subsets of a finite group GG satisfying a simple combinatorial condition (the Triple Product Property). The complexity of such an algorithm then depends on the representation theory of GG. In this paper we extend the group-theoretic framework to the setting of infinite groups. In particular, this allows us to obtain constructions in Lie groups, with favorable parameters, that are provably impossible in finite groups of Lie type (Blasiak, Cohn, Grochow, Pratt, and Umans, ITCS '23). Previously the Lie group setting was investigated purely as an analogue of the finite group case; a key contribution in this paper is a fully developed framework for obtaining bona fide matrix multiplication algorithms directly from Lie group constructions.

Keywords

Cite

@article{arxiv.2410.14905,
  title  = {Finite matrix multiplication algorithms from infinite groups},
  author = {Jonah Blasiak and Henry Cohn and Joshua A. Grochow and Kevin Pratt and Chris Umans},
  journal= {arXiv preprint arXiv:2410.14905},
  year   = {2025}
}

Comments

40 pages; only minor updates from previous version

R2 v1 2026-06-28T19:27:58.070Z