English

From braces to pre-Lie rings

Rings and Algebras 2023-10-03 v4 Group Theory

Abstract

Let AA be a brace of cardinality pnp^{n} where p>n+1p>n+1 is prime, and let ann(p2)ann (p^{2}) be the set of elements of additive order at most p2p^{2} in this brace. We construct a pre-Lie ring related to the brace A/ann(p2)A/ann(p^{2}). In the case of strongly nilpotent braces of nilpotency index k<pk<p the brace A/ann(p2)A/ann(p^{2}) can be recovered by applying the construction of the group of flows to the resulting pre-Lie ring. We don't know whether, when applied to braces which are not right nilpotent, our construction is related to the group of flows. We use powerful Lie rings associated with finite pp-groups in the study of brace automorphisms with few fixed points. As an application we bound the number of elements which commute with a given element in a brace, as well as the number of elements which multiplied from left by a given element give zero. We also study various Lie rings associated to powerful groups and braces whose adjoint groups are powerful, and show that the obtained Lie and pre-Lie rings are also powerful. We also show that braces whose adjoint groups are powerful and powerful left nilpotent pre-Lie rings are in one-to-one correspondence and that they are left and right nilpotent under some cardinality assumptions.

Keywords

Cite

@article{arxiv.2207.03158,
  title  = {From braces to pre-Lie rings},
  author = {Aner Shalev and Agata Smoktunowicz},
  journal= {arXiv preprint arXiv:2207.03158},
  year   = {2023}
}

Comments

Some corrections added in the second part of the paper, namely to the section 9 from previous version (version 3), which is now corrected and appears as section 14 in the new version. In particular theorems 12 and 13 from section 9 from previous version, about enumeration of groups, were removed

R2 v1 2026-06-24T12:16:56.980Z