Theorem · version 2

The topological three-dimensional Poincaré theorem

Statement

Every closed, simply connected topological three-manifold is homeomorphic to the standard three-sphere.

Assumptions

  • Compact Hausdorff three-manifolds without boundary; simply connected includes connectedness.

Evidence

Source reports

Formal proofs

Connections

In this problem · publication v13

Poincaré conjecture →

Primary formulation · Proved

Analogue

The four-dimensional smooth question concerns a different dimension and equivalence notion.

The three-dimensional theorem is fully proved; this analogue is not an unresolved part of it.

Details & sources
The topological three-dimensional Poincaré theorem →

Proved · version 2

Every closed, simply connected topological three-manifold is homeomorphic to the standard three-sphere.

  • Compact Hausdorff three-manifolds without boundary; simply connected includes connectedness.

Scope: Compact Hausdorff three-manifolds without boundary; simply connected includes connectedness.

The smooth four-dimensional Poincaré question →

Open · version 1

Every closed smooth four-manifold homotopy equivalent to the four-sphere is diffeomorphic to the standard smooth four-sphere.

  • This is a separate conjecture in dimension four; simple connectivity alone is insufficient for its hypothesis.

Scope: This is a separate conjecture in dimension four; simple connectivity alone is insufficient for its hypothesis.

Relationship not independently reviewed.

Connection in Poincaré conjecture →

Relationship not independently reviewed. This concerns its use in this problem.

Sources

A Lean Formalization of the Hamilton–Perelman Proof of the Three-Dimensional Poincaré Conjecture →

  • §1, Theorems 1–3; §3, release and verification → · Original passage ↗
    Recorded wording

    The authors report Lean proofs of the smooth theorem and Moise smoothing, yielding the topological theorem. Their release v0.1.3 report names commit 7a48598d35109aa99d1cc678e2724c213cdf4ff3 and audits the endpoint closures for the three standard Lean axioms, without sorryAx or project axioms.

    paraphrase · Follow the original source for authoritative statements and reuse terms.

Ziyang Qin · Yuan Liao · Ayush Khaitan · Bennett Chow · Preprint · Publication date Sep 27, 2026

Source-backed selection; publication and proof assessment are separate.

Revision & attribution

Source revision: arxiv-2609.33842v1. Observed Oct 12, 2026.

Authors report automated assistance; OpenMath has not independently assessed that workflow.

An AI-Assisted Formalization of the Poincaré Conjecture →

Zhiyuan Zhang · Axel Delaval · Leheng Chen · Jinxuan Chen · Jie Xu · Yuxuan Liao · Jiedong Jiang · Chunlei Liu · Bin Dong · Preprint · Publication date Oct 6, 2026

Source-backed selection; publication and proof assessment are separate.

Revision & attribution

Source revision: arxiv-2610.08329v1. Observed Oct 12, 2026.

Authors report automated assistance; OpenMath has not independently assessed that workflow.

Mathlib · wanted Poincaré statements →

Mathlib contributors · Project documentation

Source-backed selection; publication and proof assessment are separate.

Revision & attribution

Source revision: 9454a4c25a2b923eb55dba3098f2d6ae0484d09b. Observed Oct 12, 2026.

AI use is not reported in the selected source.

Poincaré comparator integration verification →

  • Local integration verification; verification.json beside README → · Original passage ↗
    Recorded wording

    The project’s report records successful statement comparison and Lean/Nanoda checks on 28 September 2026 for proof commit 1876d7dc2c85325a3f62ce9776af98f910c5db04, permitting only the three standard axioms. Later documentation and import commits are not the tested revision; the report is project-supplied evidence.

    paraphrase · Follow the original source for authoritative statements and reuse terms.

FrenzyMath contributors · Project documentation

Project-supplied verification report at the pinned documentation revision. The 28 September date describes verification, not publication; publication date is not established.

Revision & attribution

Source revision: 432c38f2aa5a30efb13871292d17b4a3309a496a; bibliographic metadata corrected 2026-10-12. Observed Oct 12, 2026.

Authors report automated assistance; OpenMath has not independently assessed that workflow.

Ricci Flow and the Poincaré Conjecture →

John Morgan · Gang Tian · Published · Publication date 2007

Source-backed selection; publication and proof assessment are separate.

Revision & attribution

Source revision: clay-monograph-3-2007. Observed Oct 12, 2026.

AI use is not reported in the selected source.

The Poincaré Conjecture · official description →

  • §§1–3; dimension-three comparison on page 5 → · Original passage ↗
    Recorded wording

    Milnor distinguishes topological from smooth classification and explains why the distinctions disappear in dimension three. A homology sphere alone does not satisfy the Poincaré hypothesis.

    paraphrase · Follow the original source for authoritative statements and reuse terms.

John Milnor · Published

Source-backed selection; publication and proof assessment are separate.

Revision & attribution

Source revision: clay-description-observed-2026-10-12. Observed Oct 12, 2026.

AI use is not reported in the selected source.

From Knots to Four-Manifolds →

Ciprian Manolescu · Published · Publication date 2026

Source-backed selection; publication and proof assessment are separate.

Revision & attribution

Source revision: icm-2026-doi-25M1806703. Observed Oct 12, 2026.

AI use is not reported in the selected source.

History

Statement versions

Statement versions and problem publication versions are separate. A new publication can update context or sources while retaining the same statement.

Assessment history · 1

Assessments retained in these publication records. Earlier statement versions retain their own source histories.

Proved

Solved ↗

The cited source item and version only; this is not an independent OpenMath assessment.

Observed Oct 1, 2026 · Source passage →

Source updates

Record details
Claim ID
claim-poincare-three-topological
Statement version
2
SHA-256
623f5beb594a9e239386ff338920ea89201ea8e9f3db4c974f840101fbd2c437

Publication records