English

On homological finiteness properties and free inverse monoids

Group Theory 2026-06-29 v1 Rings and Algebras

Abstract

We construct a simple and useful sufficient condition, based on actions on a lattice of idempotents, for monoids admitting homomorphisms to the monogenic free inverse monoid FIM(1)\mathrm{FIM}(1) to not be of type FP2\mathrm{FP}_2. This recovers a result of Gray and Steinberg that free inverse monoids are not of type FP2\mathrm{FP}_2. The same technique is then used to show that a finitely generated submonoid of FIM(1)\mathrm{FIM}(1) is of type FP2\mathrm{FP}_2 if and only if it is finitely presented, answering a question of Cho & Ru\v{s}kuc.

Keywords

Cite

@article{arxiv.2606.30434,
  title  = {On homological finiteness properties and free inverse monoids},
  author = {Carl-Fredrik Nyberg-Brodda},
  journal= {arXiv preprint arXiv:2606.30434},
  year   = {2026}
}

Comments

6 pages. Comments welcome!