What was already known
Whether any countable non-sofic group existed was open. Kun and Kun–Thom supplied earlier ingredients; later authors used the criterion for different non-sofic families.
AI involvement
OpenAI attributes the construction and Lean formalization to Astra. Human staff chose the problem and prepared the manuscript; later mathematicians studied and reused parts of its criterion.
OpenAI’s original disclosure assigns the argument and subsequent Lean formalization to Astra; human manuscript preparation is separately credited.
Importance
The explicit witness answers a central existence question in group theory.
Limitations
The project reports a Lean certificate for the finite-presentation and non-soficity claim. Human reviews noted convention and parameter bookkeeping issues and did not document a complete independent proof check.
Technical verification
The project reports a complete Lean certificate for the stated formal theorem. Human assessments have narrower scope; semantic matching and any manuscript gaps remain separately noted.
Independent checking
chapter-specific mathematical review of the published argument, with the limited coverage summarized in the audit
- Checker
- Chapter 3 human reviewers in the Sienicki et al. review corpus
- Scope
- non-sofic construction conventions and auxiliary-parameter hierarchy
- Basis
- Reported by the linked checker
Formal checking
Lean 4.32.0 formal certificate in NonSoficGroup.lean; comparator target for SoficGroups.SourceTopLevelCompressionFinal.exists_finitelyPresented_nonsofic_group; manifest reports zero sorry and only standard axioms
- Checker
- OpenAI ten-proofs project, Lean kernel and Comparator configuration
- Scope
- finitely presented non-sofic group
- Basis
- Reported by the linked checker
Checking a formal statement does not establish that it matches the original problem.
Human understanding
Fournier-Facio and Kun–Thom engage with and reuse the proof criterion, supporting human understanding of its expander-matching mechanism; this is not a complete check of the original manuscript.
Correction and publication history
An explicit finitely presented witness for non-soficity.
Read this published revision