Source labels openChecked July 26, 2026

Erdős Problem 352

Is there some $c > 0$ such that every measurable $A \subseteq \mathbb{R}^2$ of measure $\geq c$ contains the vertices of a triangle of area 1?

Geometry AMS 51

Mathematical statement

Is there some $c > 0$ such that every measurable $A \subseteq \mathbb{R}^2$ of measure $\geq c$ contains the vertices of a triangle of area 1?

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_352

Canonical source

Complete statement target, proof intentionally absentLean 4

theorem erdos_352 :    answer(sorry) ↔ ∃ c > (0: ℝ), ∀ A : Set ℝ², MeasurableSet A → ℙ A ≥ c.toEReal       → (∃ t : Affine.Triangle ℝ ℝ²,           (∀ p : Fin 3, t.points p ∈ A) ∧           EuclideanGeometry.triangle_area (t.points 0) (t.points 1) (t.points 2) = 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

Pinned Formal Conjectures sourceformalization erdosproblems.com/352background