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An infinite finitely presented residually finite 2-group and a finitely presented nil algebra

OpenAI groups related papers into a “family”. OpenAI’s catalogue describes this one:

Constructs an infinite finitely presented residually finite group whose elements all have finite 2-power order, answering the finitely presented Burnside problem negatively even in this class. The construction also yields an infinite-dimensional finitely presented nil associative 𝔽2-algebra and a finitely presented infinite-dimensional algebraic unitization, giving negative answers to the corresponding nilpotence and Kurosh finiteness questions. (OpenAI’s Lean note)

Lean is a language for mathematical statements and proofs that a computer can verify. The assessments below ask whether those statements express the result OpenAI describes here.

The independent assessments find that the Lean statements express only part of the result described above, or a narrower statement. Read the assessments

The paper states

Theorem 1.1

In An infinite finitely presented periodic group, 23 September 2026

Possible match to OpenAI’s description, selected from the papers’ main statements because it shares the most wording. No review confirming the selection is recorded.

The other possible matches are Theorem 1.1 in An infinite finitely presented residually finite 2-group () and Corollary 1.2 (A periodic Kazhdan group) in the same paper ().

There is an infinite periodic group with an ordinary finite presentation. More precisely, the construction below gives a unital associative \F_2-algebra R for which \St_{12}(R) is infinite, finitely presented, and periodic.

Reported proof verification
One Lean statement in the release; two independent groups report that Comparator accepted runs for this file at the version shown here.

Papers

Each paper opens as a reading page in the browser, with the PDF beside it. The statements each paper opens with are on its reading page.

An infinite finitely presented residually finite 2-group

5 October 2026, current edition.

Read it herePDF

We prove that the infinite, ordinarily finitely presented periodic Steinberg group \(\Gamma=\mathop{\mathrm{St}}\nolimits _{12}(R)\) of a companion paper is residually finite. Its finite-index subgroup \(G=\ker(\Gamma\to\mathop{\mathrm{St}}\nolimits _{12}(\mathbb F_2))\) is infinite, ordinarily finitely presented, and residually finite, and every element of G has finite 2-power order. The orders of its elements are unbounded. Phases of long words in the companion’s graded algebra allow finite degree truncations to detect all elements of Γ, including the central kernel.

An infinite finitely presented periodic group

23 September 2026, current edition.

Read it herePDF

We construct an infinite group with an ordinary finite presentation in which every element has finite order, answering the finitely presented Burnside question negatively. We also construct an infinite-dimensional finitely presented nonunital nil associative algebra over 𝔽2 that is Jacobson radical but not nilpotent. Its unitization is finitely presented, algebraic, and infinite-dimensional. These algebras answer the finitely presented nil- and radical-algebra nilpotence questions and the finite-presentation version of Kurosh’s algebraic finiteness question negatively.

One Lean statement in this family

Lean is a language for mathematical statements and proofs that a computer can verify. The Lean statement below is shown beside its possible paper counterpart, with the reason they were linked.

For a configured theorem, the Comparator program tests whether OpenAI’s separate proof proves the exact Lean statement using only the allowed axioms. Some statement files instead configure definitions for comparison by name and type. Acceptance does not establish that a formal statement means the same thing as the paper’s theorem.

PeriodicGroup

The paper states

The words they share: algebra, finite, finitely, gives, group, infinite, periodic, presented.

Possible Lean counterpart

Selected from shared wording. No review of whether the statements mean the same thing is recorded.

Infinite finitely presented periodic group

PeriodicGroup.lean, the release lists it as a supporting statement.

theorem thm_main : MainStatement ∧ BurnsideStatement := by  sorry

This file states the theorem with sorry, a placeholder, in place of its proof. OpenAI supplies a separate proof file. Comparator tests whether that proof proves the statement here.

two independent groups report that Comparator accepted runs for this Lean statement file: cert-machine; MathVet. Who ran the proof-verification program

  • cert-machine records it as “CERTIFIED”.
  • MathVet records it as “comparator-sandboxed-pass”.

Read the complete Lean statement

Independent comparisons and proof-verification reports

Does the Lean express the advertised result?

Neither group finds that the Lean statements express or imply the whole advertised result. They describe what the statements express in different terms.

MathVet and Carlos Toledo’s cert-machine independently assessed whether this family’s Lean statements express the whole result OpenAI describes in its catalogue. These are assessments of the family as a whole, not of each paper theorem separately.

MathVet finds that the Lean statements express a weaker statement than the advertised result (their term: “weaker-statement”).

Their note: thm_main : MainStatement ∧ BurnsideStatement only gives an infinite finitely presented PERIODIC group (Periodic G := ∀ g, ∃ m > 0, g^m = 1, namely Steinberg 12 R for some F₂-algebra R, and a general ∃ G version). The summary’s group is a residually finite 2-group (every element of 2-power order) with accompanying nil-algebra consequences; neither ‘residually finite’ nor ‘2-power order’ nor the algebra statements is stated (docs: 'no common exponent is asserted... separate nil-algebra and radical-algebra conclusions are outside these selected statements'). The negative answer to the finitely presented Burnside problem itself is covered.

Definitions the group asks readers to compare with the paper: Steinberg n R := PresentedGroup {r | SteinbergRel n R r} with relations x_{ij}(a+b) = x_{ij}(a) x_{ij}(b), [x_{ij}(a), x_{kl}(b)] = 1 for p.col ≠ q.row ∧ p.row ≠ q.col, and [x_{ij}(a), x_{jk}(b)] = x_{ik}(ab): the standard Steinberg presentation, hand-written (the carrier ring R is existentially chosen).

“weaker-statement”, in their words: The challenge statements do not imply the headline claim: they state a nontrivially weaker statement.

Their method: An independent, model-assisted, pre-referee reading of each family’s challenge statements against its headline claim under a published rubric (PROTOCOL.md), with its own Comparator runs per challenge.

cert-machine finds that the Lean statements express a narrower statement than the advertised result (their term: “NARROWER — UNLINKED”).

The gap they name: Residual finiteness and the 2-power order of every element (the October 5 manuscript’s contribution; undeclared), plus the nil algebra and algebraic-unitization clause (declared outside).

“NARROWER — UNLINKED”, in their words: The challenge statements state less than the headline; the missing part comes from a paper the Lean note does not link.

Their method: Every Comparator challenge re-run on Linux with nanoda switched on, decided by a preregistered rule.

OpenAI’s own note on what its Lean covers

The finitely presented Burnside question asks whether a finitely presented group in which every element has finite order must be finite. The formalization gives a negative answer by constructing an infinite finitely presented periodic group, including a witness realized as a Steinberg group over an algebra of characteristic two. Periodicity means that each element has some finite order; no common exponent is asserted. The paper’s separate nil-algebra and radical-algebra conclusions are outside these selected statements.

AI-drafted comparisons, with no recorded human review

  • Infinite finitely presented periodic group PeriodicGroup

    Unreviewed AI draft: states a paper’s theorem as the paper does. States the main theorem: an infinite finitely presented periodic group, realised as St₁₂(R) for an F₂-algebra R. The nil-algebra conclusions and the Kazhdan corollary are not part of the statement.

Who ran the proof-verification program?

These groups report running Comparator with the release’s Lean statement files. For a configured theorem, it verifies OpenAI’s separate proof against the exact statement; some files instead configure definitions for comparison by name and type. Each row is the named group’s report. Atlas has not repeated the runs.

These reports do not list the software versions, proof-verification programs, axioms, time or memory in separate fields. Any such details in a report’s prose are reproduced below.

Infinite finitely presented periodic group PeriodicGroup

Two reports, all at the release’s recorded version.

Reported byTheir wordTheir accountDateOriginal report
cert-machine“CERTIFIED”Re-run through Comparator with the independent nanoda kernel switched on: Lean’s kernel and nanoda both accept OpenAI’s solution.10 October 2026Original report
MathVet“comparator-sandboxed-pass”Re-run through Comparator in a sandboxed virtual machine: accepted.8 October 2026Original report

What these papers cite in the release, and what cites them

These links come from the papers’ bibliographies. A citation records that one paper cites another; how each cited result is used has not been examined here.

Within this family

Papers elsewhere in the release that this family’s papers cite

This family’s papers cite no paper elsewhere in the release.

Papers elsewhere in the release that cite this family’s papers

No paper elsewhere in the release cites this family’s papers.

References outside the release

Each paper’s outside references are listed with it on its reading page, where each citation is placed. Every outside work cited in the release: References outside the release

Explain a result, compare statements or propose a correction

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What people have said

Commentary on this family by others, dated and credited. It is commentary, not a finding.

  • An unsigned public tier list, the OpenAI Math Tier List, classes it as a counterexample and rates its significance, if it holds up, as “Career-defining publication”. The page says that nothing on it is verified.

    Author not stated. Source

Questions awaiting review

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Read the Lean statement against the paper

  • An AI agent drafted an assessment of which part of the paper this Lean statement expresses. No named human review is recorded. Open the form

Identify the theorem the catalogue describes

  • Family 247 The theorem shown was selected from shared wording with OpenAI’s description. Atlas records no review confirming that it is the theorem the description means. Open the form

Address a question raised in an independent assessment

Compare the proposed paper and Lean matches

  • Family 247 Atlas records no review of whether each linked Lean statement and paper theorem mean the same thing. Open the form