Skip to content

Erdős problem 94

Suppose nn points in R2\mathbb{R}^2 determine a convex polygon and the set of distances between them is {u1,…,ut}\{u_1,\ldots,u_t\}. Suppose uiu_i appears as the distance between f(ui)f(u_i) many pairs of points. Then ∑if(ui)2≪n3.\sum_i f(u_i)^2 \ll n^3.

Sources

The source's own material, retained exactly.

4 retained statements36c6d0fef71a

Open selected source

FormalConjectures/ErdosProblems/

94.lean

Retained formal statement2 of 4

Lefmann and Theile [LeTh95] prove a stronger version of this question, that ∑if(ui)2≪n3\sum_i f(u_i)^2 \ll n^3 under the weaker assumption that no three points are on a line.

FormalConjectures/ErdosProblems/94.leanErdos94.erdos_94.variants.no_three_on_a_line4 linesExact file
∃ C > 0,  ∀ (P : Finset (EuclideanSpace ℝ (Fin 2))),    EuclideanGeometry.NonTrilinear ↑P →      ∑ u ∈ EuclideanGeometry.distanceSet P, ↑(EuclideanGeometry.distanceMultiplicity P u) ^ 2 ≤ C * ↑P.card ^ 3
SolvedStatement only, no proofformal statement reference