What the papers state
There exist closed connected aspherical topological four-manifolds M and N that are homotopy equivalent but not homeomorphic. Their common fundamental group is word-hyperbolic.
There exist a closed connected aspherical topological four-manifold M and a homotopy equivalence f\colon M\to M such that no homeomorphism M\to M is homotopic to f.
The release does not say which paper theorem its catalogue describes. Both statements above are shown whole: the paper’s main theorem first, then the statement that shares the most wording with the description. The atlas has not reviewed either choice.
- Reported proof verification
- The release has no Lean statement for this family. The papers are available to read and assess.
Papers
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4 October 2026, current edition.
Read it herePDF
We construct closed connected aspherical topological four-manifolds that are homotopy equivalent but not homeomorphic, disproving the homeomorphism-existence formulation of the Borel conjecture in dimension four. Their common fundamental group is word-hyperbolic. One of the manifolds also has a self-homotopy equivalence not homotopic to a homeomorphism.
Lean statements
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Independent comparisons and proof-verification reports
Does the Lean express the advertised result?
The release contains no Lean statement for this family, so there is no formal statement to compare with OpenAI’s description.
What these papers cite in the release, and what cites them
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Papers elsewhere in the release that this family’s papers cite
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
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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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Identify the theorem the catalogue describes
- Family 320 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
State the result in Lean
- Family 320 The release has no Lean statement for this family. Open the form