Erdős problem 97
Does every convex polygon have a vertex with no other 4 vertices equidistant from it?
Sources
FormalConjectures/ErdosProblems/
97.lean
Retained formal statement
Fishburn and Reeds [FiRe92] also proved that the smallest for which there exists a convex -gon and a cut of its vertices such that for all , and for all , is .
sInf {n | ∃ V A B, n = V.card ∧ EuclideanGeometry.ConvexIndep ↑V ∧ A.Nonempty ∧ B.Nonempty ∧ Erdos97.IsCut V A B ∧ Erdos97.HasNUnitDistancePointsOn 3 B A ∧ Erdos97.HasNUnitDistancePointsOn 3 A B} = 20SolvedStatement only, no proof