English

On identities in connected topological groups

General Topology 2025-01-14 v2 Group Theory

Abstract

In 1957, Nemytskii proved the following fact: if in a locally compact or in an Abelian connected group there is a neighborhood of the identity in which some identity holds, then it holds in the entire group. The following question was also posed there: Let G be a connected topological group. In some neighborhood of the identity of the group G the identity x3=1x^3=1 holds. Is it true that then the identity x3=1x^3=1 holds in the entire group GG? The same question is posed for the identity gx2=x2ggx^2 = x^2g, where gg is a fixed element of the group. Platonov formulated the following generalized formulation of the Mytselsky problem: for a topological connected group, is it true that if the identity holds in a neighborhood of the identity, then the identity holds everywhere? In this paper, a negative answer to Platonov's question is given, the following theorem is proven: if n>1010n > 10^{10} is odd, then there exists a connected topological group in which the identity xn=1x^n=1 holds in some neighborhood of unity, but not in the entire group.

Cite

@article{arxiv.2406.05203,
  title  = {On identities in connected topological groups},
  author = {Evgenii Reznichenko and Il'ya Zyabrev},
  journal= {arXiv preprint arXiv:2406.05203},
  year   = {2025}
}

Comments

in Russian language

R2 v1 2026-06-28T16:57:46.148Z