All open problems
Source labels openChecked July 26, 2026
Inscribed square problem
Inscribed square problem* Does every Jordan curve admit an inscribed square?
Mathematical statement
Inscribed square problem* Does every Jordan curve admit an inscribed square?
Statement source: Wikipedia statement material
Statement terms: CC-BY-SA-4.0
Attributed source material. Reuse must follow the linked attribution and share-alike terms.
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
inscribed_square_problem
Complete statement target, proof intentionally absentLean 4
theorem inscribed_square_problem : answer(sorry) ↔ ∀ (γ : Circle → ℝ²) (hγ : IsEmbedding γ), ∃ t₁ t₂ t₃ t₄, IsRectangle (γ t₁) (γ t₂) (γ t₃) (γ t₄) 1 := 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