English

Connectivity of partial basis complexes of freely decomposable groups

Geometric Topology 2025-09-26 v2 Group Theory

Abstract

We show that the complex of partial bases of the free group of rank nn, where vertices are seen up to conjugation, is Cohen--Macaulay of dimension n1n-1. This positively answers a conjecture raised by Day and Putman. We prove our results in the more general context of freely decomposable groups.

Keywords

Cite

@article{arxiv.2410.17121,
  title  = {Connectivity of partial basis complexes of freely decomposable groups},
  author = {Benjamin Brück and Kevin Ivan Piterman},
  journal= {arXiv preprint arXiv:2410.17121},
  year   = {2025}
}

Comments

12 pages; v2: accepted version with improved exposition and further background in the introduction; to appear in Bull. Lond. Math. Soc