Simple F∞ overgroups of groups with decidable word problem

OpenAI

Every finitely generated group with decidable word problem embeds injectively in a nontrivial simple group of type F∞, meaning it has a classifying CW complex with finitely many cells in each dimension.

Sources for this record

What was already known

Boone and Higman asked for a finitely presented simple overgroup. The published Boone–Higman record concerns that weaker conclusion; this manuscript also uses earlier human embedding theorems.

AI involvement AI-led

OpenAI credits its internal model with this manuscript family. The construction uses earlier human embedding theorems as inputs; no human-origin step in the new higher-finiteness argument is documented.

Institutional AI authorship and the release’s production account support AI-led mathematical work; autonomous generation of each lemma is not established.

Importance Major

Strengthens the Boone–Higman result to higher finiteness for every eligible group.

Limitations

The source-reported Lean theorem matches the stated embedding, but its build and the correspondence of formal definitions to the manuscript were not independently established in the review.

Technical verification Formal (Lean 4 / mathlib)

The Lean documentation explicitly states the higher-finiteness strengthening and a comparator for exactly this embedding claim. The formalized statement includes decidable word problem, a nontrivial simple target, type F_infinity and an injective homomorphism.

Formal checking

Formal theorem matched to SimpleOvergroups comparator and scope documentation

Checker
Lean 4/mathlib SimpleOvergroups development
Scope
Every finitely generated decidable-word-problem group embeds in a nontrivial simple F_infinity group
Basis
Reported by the linked checker
Evidence source

Checking a formal statement does not establish that it matches the original problem.

Human understanding Few

The release names no human interpreter of the model’s ring-encoding, homological and stabilizer argument; Few is the evidence default.

Correction and publication history

2026-10-18 · publication

If correct, strengthens the Boone–Higman result to higher finiteness for every eligible group.

Read this published revision