English

The BNSR-invariants of the Houghton groups, concluded

Group Theory 2020-02-19 v2 Geometric Topology

Abstract

We give a complete computation of the BNSR-invariants Σm(Hn)\Sigma^m(H_n) of the Houghton groups HnH_n. Partial results were previously obtained by the author, with a conjecture about the full picture, which we now confirm. The proof involves covering relevant subcomplexes of an associated CAT(0)CAT(0) cube complex by their intersections with certain locally convex subcomplexes, and then applying a strong form of the Nerve Lemma. A consequence of the full computation is that for each 1mn11\le m\le n-1, HnH_n admits a map onto Z\mathbb{Z} whose kernel is of type Fm1F_{m-1} but not FmF_m, and moreover no such kernel is ever of type Fn1F_{n-1}.

Keywords

Cite

@article{arxiv.1808.00634,
  title  = {The BNSR-invariants of the Houghton groups, concluded},
  author = {Matthew C. B. Zaremsky},
  journal= {arXiv preprint arXiv:1808.00634},
  year   = {2020}
}

Comments

v2: Accepted version, to appear in Proc. Edinb. Math. Soc. 10 pages