English

Approximability of word maps by homomorphisms

Group Theory 2017-08-03 v1

Abstract

Generalizing a recent result of Mann, we show that there is an explicit function f:(0,1](0,1]f:\left(0,1\right]\rightarrow\left(0,1\right] such that for every reduced word ww, say in dd variables, there is an explicit reduced word vv in at most 3d3d variables (nontrivial if the length of ww is at least 22) such that for all ρ(0,1]\rho\in\left(0,1\right], the following holds: If GG is any finite group for which the word map wG:GdGw_G:G^d\rightarrow G agrees with some fixed homomorphism GdGG^d\rightarrow G on at least ρGd\rho|G|^d many arguments, then the word map vG:G3dGv_G:G^{3d}\rightarrow G has a fiber of size at least f(ρ)G3df(\rho)|G|^{3d}. We also discuss some applications of this result.

Keywords

Cite

@article{arxiv.1708.00477,
  title  = {Approximability of word maps by homomorphisms},
  author = {Alexander Bors},
  journal= {arXiv preprint arXiv:1708.00477},
  year   = {2017}
}

Comments

6 pages

R2 v1 2026-06-22T21:04:02.641Z