English

Non-finitely Generated Maximal Subgroups of Context-free Monoids

Group Theory 2021-11-02 v2 Rings and Algebras

Abstract

A finitely generated group or monoid is said to be context-free if it has context-free word problem. In this note, we give an example of a context-free monoid, none of whose maximal subgroups are finitely generated. This answers a question of Brough, Cain & Pfeiffer on whether the group of units of a context-free monoid is always finitely generated, and highlights some of the contrasts between context-free monoids and context-free groups.

Keywords

Cite

@article{arxiv.2107.12861,
  title  = {Non-finitely Generated Maximal Subgroups of Context-free Monoids},
  author = {Carl-Fredrik Nyberg-Brodda},
  journal= {arXiv preprint arXiv:2107.12861},
  year   = {2021}
}

Comments

10 pages, 51 references. Final submitted version

R2 v1 2026-06-24T04:33:58.345Z