English

BNSR invariants and $\ell^2$-homology

Geometric Topology 2024-01-12 v1 Algebraic Topology Functional Analysis Group Theory K-Theory and Homology

Abstract

We prove that if the nnth 2\ell^2-Betti number of a group is non-zero then its nnth BNSR invariant over Q\mathbb{Q} is empty, under suitable finiteness conditions. We apply this to answer questions of Friedl--Vidussi and Llosa Isenrich--Py about aspherical K\"ahler manifolds, to verify some cases of the Singer Conjecture, and to compute certain BNSR invariants of poly-free and poly-surface groups.

Keywords

Cite

@article{arxiv.2401.05545,
  title  = {BNSR invariants and $\ell^2$-homology},
  author = {Sam Hughes and Dawid Kielak},
  journal= {arXiv preprint arXiv:2401.05545},
  year   = {2024}
}

Comments

31 pages, comments welcome!