Conjectures.io

approved

Erdős problem 96

Disproved

Strictly convex planar point sets can have superlinearly many unit-distance pairs, disproving the proposed universal linear bound.

Submitted by JenW1N

Lean verification:
Passed
Conjectures review:
Approved
Reward:
Eligible

The PDF is a working mathematical exposition. Lean verification applies to the formal source, not the prose.

Approved in review on 14 Sept 2026

Review decision

Approved in reviewREVIEW_APPROVED

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Approved · decided 14 Sept 2026

Formal statement

True ↔ (fun n => ↑(Erdos96.maxConvexUnitDistances n)) =O[Filter.atTop] fun n => ↑n

Verification report

Every box below had to hold before the proof counted. They are grouped in the order the verifier reaches them.

The task it was checked against

  • Manifest valid — Passed

    The task bundle held together: the exact file set, a strict manifest, and every trusted hash matching the bytes on disk.

  • Task commitment matches — Passed

    The bundle digest the submission committed to is the digest of the bundle that was actually verified.

  • Production task — Passed

    The task came from the production pool rather than a test fixture.

  • Trusted file hashes match — Passed

    The pinned dependencies agree across the manifest, the lockfile and the checkout, down to the same Formal Conjectures commit.

The submission and the sandbox

  • Submission policy respected — Passed

    The submitted source passed the static scan: no imports, no axiom declarations, no sorry, no native_decide, no unsafe options.

  • Production sandbox — Passed

    The run happened under real isolation, Landrun with seccomp, and the sandbox passed its own live self-test before the proof was touched.

The trusted build

  • Challenge built — Passed

    The trusted Challenge.lean, which contains no miner code, compiled on its own.

  • Source type hash matches — Passed

    The source theorem in the compiled environment still hashes to the type recorded in the task, so the statement has not drifted upstream.

The kernel's verdict

  • Solution built — Passed

    The submitted Solution.lean compiled.

  • Statement unchanged — Passed

    The theorem the proof establishes has exactly the same canonical type as the task's target - it was not weakened or restated.

  • Only permitted axioms — Passed

    The transitive axiom closure of the proof stays inside the axioms this task permits.

  • Lean kernel accepted — Passed

    The Lean kernel replayed the proof and accepted it.

  • Nanoda accepted — Not run

    A second kernel, written independently of Lean's, also accepted the proof.

One kernel, not two

This task does not require a second, independent kernel, so Nanoda was not run. The verdict rests on a single kernel implementation.

Theorems established

  • Bounty.target

Stage COMPLETED · Axioms permitted: propext, Quot.sound, Classical.choice