PreprintCC BY 4.0arXiv
ℓ2-Betti numbers and Σ-invariants of graph products of cyclic groups and their automorphisms
Abstract
We study the ℓ2-Betti numbers of graph products of cyclic groups. We relate these invariants to the ℓ2-Betti numbers of right-angled Artin groups and obtain explicit formulas in several cases determined by the structure of the finite-order vertices in the defining graph. In particular, we consider the cases where these vertices form a clique or have identical links, and derive a formula for the first ℓ2-Betti number when the defining graph has exactly two finite-order vertices. We also compute the BNSR-invariants of graph products of cyclic groups and the first ℓ2-Betti number of their automorphism groups when the defining graph has at most two finite-order vertices.
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BibTeX
@misc{escartinferrer2026ℓ2betti,
title = {{$\ell^2$-Betti numbers and $Σ$-invariants of graph products of cyclic groups and their automorphisms}},
author = {Marcos Escartín-Ferrer},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.09704},
eprint = {2610.09704},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.09704},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - ℓ^2-Betti numbers and Σ-invariants of graph products of cyclic groups and their automorphisms
AU - Marcos Escartín-Ferrer
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2610.09704
UR - https://arxiv.org/abs/2610.09704
AB - We study the ℓ^2-Betti numbers of graph products of cyclic groups. We relate these invariants to the ℓ^2-Betti numbers of right-angled Artin groups and obtain explicit formulas in several cases determined by the structure of the finite-order vertices in the defining graph. In particular, we consider the cases where these vertices form a clique or have identical links, and derive a formula for the first ℓ^2-Betti number when the defining graph has exactly two finite-order vertices. We also compute the BNSR-invariants of graph products of cyclic groups and the first ℓ^2-Betti number of their automorphism groups when the defining graph has at most two finite-order vertices.
ER -