English

On the $\Sigma^1$ and $\Sigma^2$-invariants of Artin groups

Group Theory 2025-07-15 v3

Abstract

We prove the Σ1\Sigma^1-conjecture for two families of Artin groups: Artin groups such that there exists a prime number pp dividing l(e)2\frac{l(e)}{2} for every edge ee with even label >2>2 and balanced Artin groups. The family of balanced Artin groups extends two previously studied families: the one considered by Kochloukova in arXiv:2009.14269, and the family of coherent Artin groups. We state a conjecture on the Σ2\Sigma^2-invariant for Artin groups satisfying the K(π,1)K(\pi,1)-conjecture. The conjecture is proven to be true for two significant families: 22-dimensional and coherent Artin groups. In the 22-dimensional case we are able to compute Σn\Sigma^n for all n2n\geq 2 and to derive finiteness properties of the derived subgroup.

Keywords

Cite

@article{arxiv.2501.08692,
  title  = {On the $\Sigma^1$ and $\Sigma^2$-invariants of Artin groups},
  author = {Marcos Escartín Ferrer},
  journal= {arXiv preprint arXiv:2501.08692},
  year   = {2025}
}

Comments

19 pages. Fixes a mistake in the proof of Theorem 1.2, by refining the definition of balanced Artin groups