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Torsion-freeness problem for matrix groups
Abstract
We establish three results on decision problems for finitely generated matrix groups, based on fiber products: • The torsion-freeness problem is undecidable for subgroups of SL4(ℤ), • There exists a finitely generated subgroup G of SL4(ℤ) with undecidable square root problem, • No algorithm can, on input a tuple of invertible matrices, output the list of marked finite quotients of the group they generate.
Related
- Counterexamples to torsion-freeness in the K-theory of crystallographic group C*-algebras
- Multiplicator freeness for restricted-ramification Galois groups over global function fields
- On growth and torsion of groups
- Uniform small cancellation in torsion-free hyperbolic groups
- Divisibility and torsion in higher Chow groups over arithmetic fields
BibTeX
@misc{dong2026torsionfreeness,
title = {{Torsion-freeness problem for matrix groups}},
author = {Ruiwen Dong and Emmanuel Rauzy},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.15378},
eprint = {2609.15378},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.15378},
}
RIS
TY - UNPB
TI - Torsion-freeness problem for matrix groups
AU - Ruiwen Dong
AU - Emmanuel Rauzy
PY - 2026
DA - 2026/09/14
PB - arXiv
DO - 10.48550/arxiv.2609.15378
UR - https://arxiv.org/abs/2609.15378
AB - We establish three results on decision problems for finitely generated matrix groups, based on fiber products: • The torsion-freeness problem is undecidable for subgroups of SL_4(ℤ), • There exists a finitely generated subgroup G of SL_4(ℤ) with undecidable square root problem, • No algorithm can, on input a tuple of invertible matrices, output the list of marked finite quotients of the group they generate.
ER -