ProofAtlas

Lean evidence record

No Retraction from the Disk onto Its Boundary Circle: Lean evidence

This technical record binds the exact theorem statement to its commit-pinned Lean source, checker results, assumptions, and publication-review status.

Read theorem page
Lean buildpassed
Unfinished proof stepsNone
Publication reviewsAccepted

Line counts exclude blank lines; comments and documentation count. The total is the commit-pinned first-party Lean import closure; Mathlib and other third-party dependencies are excluded.

Exact formal proposition

Hypotheses and conclusion

This is the meaningful proposition proved by the checked wrapper declaration. It is extracted from the same commit-pinned Lean source.

def NoRetractionDiskCircleStatement : Prop :=
  ¬ ∃ r : ClosedDisk → UnitCircle, RetractionToCircle r
Definitions used in this proposition

ClosedDisk

abbrev ClosedDisk : Type :=
  {z : ℂ // ‖z‖ ≤ 1}

UnitCircle

abbrev UnitCircle : Type :=
  {z : ℂ // ‖z‖ = 1}

RetractionToCircle

def RetractionToCircle (r : ClosedDisk → UnitCircle) : Prop :=
  Continuous r ∧ ∀ z : UnitCircle, r (boundaryInclusion z) = z
Lean wrapper declaration

The checked endpoint names the expanded proposition above. Both come from the same commit-pinned source.

theorem noRetractionDiskCircle :
    NoRetractionDiskCircleStatement
Open main Lean file

Technical evidence record

Source identity, checker results, and assumptions

Main Lean declaration
noRetractionDiskCircle
Source commit
ad23ba105ce2

Mechanical evidence

How Lean checked the proof

These fields support the exact Lean declaration, not a broader informal claim.

Artifact ID
artifact.known-no-retraction-disk-circle.no-retraction.v002
Declarations covered by recorded evidence
AtlasKnownTheorems.NoRetractionDiskCircle.noRetractionDiskCircle
AtlasKnownTheorems.NoRetractionDiskCircle.NoRetractionDiskCircleStatement
Lean build
passed
Recorded build time
6.7 s one machine-dependent evidence run, not a benchmark
Evidence collected
· clean-source provenance recorded
Unfinished proof check
passed
Lean toolchain
leanprover/lean4:v4.29.1
Recorded source commit
ad23ba105ce255996424a947d1dcea9a9b69ac97
Source SHA-256
sha256:7e1abb56339067191cf50f8b861b41843c4d67bc7453f2aceeb70175914778d0
Statement alignment
accepted

Lean foundations

Standard foundations used by the proof

Lean reports the logical foundations below through Mathlib. They are standard proof-system foundations, not conjectural mathematical assumptions about this theorem. The recorded closure stays within the approved classical_mathlib_standard profile, with no unexpected axiom or unfinished-proof placeholder.

  • Classical.choice
  • Quot.sound
  • propext

Files and machine-readable evidence

Reproduce or inspect the recorded check

Use the complete first-party source bundle for reconstruction, or inspect the exact main file and checker evidence separately. Mathlib and other third-party dependencies are identified but not rebundled.

Checked source + agent continuation package · 1 Lean file · 1 evidence record · Download ZIPBrowse counted source onlineDownload main Lean fileDownload checker evidence (JSON)Download Apache-2.0 license

Review bindings

Publication reviews accepted

All four required publication-review gates are accepted for the retained presentation of this exact theorem. The review bindings are recorded separately from the Lean build and do not broaden the formal statement.

Read the publication-review details