Erdős problem 189
If is finitely coloured then must there exist some colour class which contains the vertices of a rectangle of every area?
Sources
FormalConjectures/ErdosProblems/
189.lean
Retained formal statement
Seems to be open, as of January 2025.
¬Erdos189.Erdos189For (fun a b c d => (affineSpan ℝ {a, b}).Parallel (affineSpan ℝ {c, d}) ∧ (affineSpan ℝ {a, d}).Parallel (affineSpan ℝ {b, c})) fun a b c d => dist a b * dist b c * (EuclideanGeometry.oangle a b c).sinOpenStatement only, no proof