PreprintCC BY 4.0arXiv
Every countable group embeds in a group of type FPn
Abstract
For every integer n≥2, we prove that every countable group embeds in a group of type FPn. We also construct a group of type Fn containing a copy of every recursively presented group. Consequently, a finitely generated group embeds in a group of type Fn if and only if it is recursively presented. This answers questions of Fournier-Facio and Zaremsky, and confirms a suggestion of Gromov. An appendix combines the construction with the controlled-filling argument in a subsequently released OpenAI preprint to prove that every countable group embeds in a two-generator group of type FP∞.
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BibTeX
@misc{bartholdi2026every,
title = {{Every countable group embeds in a group of type $\mathrmFP_n$}},
author = {Laurent Bartholdi and Roman Mikhailov},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.37562},
eprint = {2609.37562},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.37562},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Every countable group embeds in a group of type FP_n
AU - Laurent Bartholdi
AU - Roman Mikhailov
PY - 2026
DA - 2026/10/08
PB - arXiv
DO - 10.48550/arxiv.2609.37562
UR - https://arxiv.org/abs/2609.37562
AB - For every integer n≥2, we prove that every countable group embeds in a group of type FP_n. We also construct a group of type F_n containing a copy of every recursively presented group. Consequently, a finitely generated group embeds in a group of type F_n if and only if it is recursively presented. This answers questions of Fournier-Facio and Zaremsky, and confirms a suggestion of Gromov. An appendix combines the construction with the controlled-filling argument in a subsequently released OpenAI preprint to prove that every countable group embeds in a two-generator group of type FP_∞.
ER -