English

Engel probability in wreath products of $p$-groups

Group Theory 2026-07-13 v1

Abstract

We give upper and lower bounds for the number of solutions of the equation en(x,y)=ge_n(x,y) = g in the group Wk=(CpCpk)2W_k=(C_p\wr C_{p^k})^2, where en(x,y)e_n(x,y) is the nn-th Engel word and gWkg\in W_k. We obtain several corollaries from this. First, we prove a stronger version of the Amit-Ashurst conjecture for Engel words in WkW_k. We also prove that Engel words are not probabilistic identities in profinite groups with arbitrarily large wreath product quotients WkW_k. To conclude, we construct closed subsets of (CpZp)2(C_p\wr\Z_p)^2 with positive Haar measure, empty-interior, and which are the preimage of an Engel word map.

Keywords

Cite

@article{arxiv.2607.11605,
  title  = {Engel probability in wreath products of $p$-groups},
  author = {Iker de las Heras and Tommaso Toti and Matteo Vannacci},
  journal= {arXiv preprint arXiv:2607.11605},
  year   = {2026}
}

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19 pages