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Source labels openChecked July 26, 2026

WikipediaCombinatorics

Sparse Ruler

Wichmann's conjecture on optimal rulers.* Every optimal ruler with more than 1313 segments is a Wichmann ruler W(r,s)W(r, s) (up to reflection, i.e. reversing the segment list). Posed by Wichmann [Wi63]; the finitely many known exceptions all have at most $13...

Mathematical statement

Wichmann's conjecture on optimal rulers.* Every optimal ruler with more than 1313 segments is a Wichmann ruler W(r,s)W(r, s) (up to reflection, i.e. reversing the segment list). Posed by Wichmann [Wi63]; the finitely many known exceptions all have at most 1313 segments (lengths 1,13,17,23,581, 13, 17, 23, 58), and no further exceptions are known up to length 213213.

Statement source: Wikipedia statement material

Statement terms: CC-BY-SA-4.0

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Statement artifacts, not proofs

These records expose exact Lean propositions and statement-only wrappers. Defining a proposition does not supply a proof of it. A placeholder-bearing target also contains no proof. Elaboration checks syntax and types; it does not certify that a formalization perfectly captures every nuance of the informal problem.

Pinned Lean formulation 1

wichmann_conjecture

Canonical source
Complete statement target, proof intentionally absentLean 4
theorem wichmann_conjecture {g : List } (hopt : IsOptimal g) (hseg : 13 < g.length) :     r s : , g = wichmannGaps r s  g = (wichmannGaps r s).reverse := by  sorry
Statement source
Formal Conjectures
Lean version
v4.27.0
Placeholder
Present; no proof artifact
Source evidence
Pinned source index
Fidelity review
Community formulation

References