All open problems
Source labels openChecked July 26, 2026

Erdős ProblemsCombinatorics

Erdős Problem 723

If there is a finite projective plane of order nn then must nn be a prime power?

Mathematical statement

If there is a finite projective plane of order nn then must nn be a prime power?

Statement source: Erdős Problems 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

erdos_723

Canonical source
Complete statement target, proof intentionally absentLean 4
theorem erdos_723 :    answer(sorry)   {P L : Type} (_: Membership P L) (_ : Fintype P) (_ : Fintype L),       pp : ProjectivePlane P L, IsPrimePow pp.order := 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