All open problems
Source labels openChecked July 26, 2026

PapersCombinatorics

Conjectures about Latin Squares

MOLS existence problem: determine exactly which orders n admit a complete set of n - 1 mutually orthogonal latin squares.

Mathematical statement

MOLS existence problem: determine exactly which orders n admit a complete set of n - 1 mutually orthogonal latin squares.

Equivalently, this asks for which orders affine planes of order n exist. Complete sets are known for prime-power orders; the smallest currently unresolved order is 12.

Statement source: Papers statement material

Statement terms: Source-specific

Source-specific terms. Therefore does not assert reuse rights beyond attributed display.

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

molsExistenceProblem

Canonical source
Complete statement target, proof intentionally absentLean 4
theorem molsExistenceProblem : answer(sorry) = {n :  | HasCompleteMOLS n} := 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