6.35 (1978)

Solved

(R. Bieri, R. Strebel). Let $\mathfrak{o}$ be an associative ring with identity distinct from zero. A group $G$ is said to be almost finitely presented over $\mathfrak{o}$ if it has a presentation $G = F/R$ where $F$ is a finitely generated free group and the $\mathfrak{o}G$-module $R/[R, R]\otimes_{\mathbb{Z}} \mathfrak{o}$ is finitely generated. It is easy to see that every finitely presented group $G$ is almost finitely presented over $\mathbb{Z}$ and therefore also over an arbitrary ring $\mathfrak{o}$. Is the converse true?

Progress

No, it is not true (M. Bestvina, N. Brady, Invent. Math., 129, no. 3 (1997), 445–470).

Comments

All comments are the responsibility of the user. Comments appearing on this page are not verified for correctness. Please keep posts mathematical and on topic. If you want to submit a proof (or a partial proof), please use the dedicated proof submission form rather than posting it in the comments.
Order by newest first or oldest first.

No comments yet. Be the first to comment.

Proof claims

Proof claims are the responsibility of the submitter. Appearance here does not mean the claim has been checked for mathematical correctness. Moderators only screen for spam, abuse, and obviously low-effort submissions.

No proof claims yet.