English

Sigma invariants for partial orders on nilpotent groups

Group Theory 2023-11-02 v1

Abstract

We prove that a map onto a nilpotent group QQ has finitely generated kernel if and only if the preimage of the positive cone is coarsely connected as a subset of the Cayley graph for every full archimedean partial order on QQ. In case QQ is abelian, we recover the classical theorem that NN is finitely generated if and only if S(G,N)Σ1(G)S(G,N) \subseteq \Sigma^1(G). Furthermore, we provide a way to construct all such orders on nilpotent groups. A key step is to translate the classical setting based on characters into a language of orders on GG.

Keywords

Cite

@article{arxiv.2311.00620,
  title  = {Sigma invariants for partial orders on nilpotent groups},
  author = {Kevin Klinge},
  journal= {arXiv preprint arXiv:2311.00620},
  year   = {2023}
}

Comments

21 pages, comments welcome

R2 v1 2026-06-28T13:08:43.900Z