Erdős problem 90
Conjectured upper bound on how many pairs among points in the plane can be exactly one unit apart.
Sources
FormalConjectures/ErdosProblems/
90.lean
Retained formal statement
Constructive form of the disproof. There is an absolute constant such that infinitely many admit a configuration realising at least unit distances.
This is the qualitative content of Theorem 1.1 of Alon–Bloom–Gowers–Litt–Sawin–Shankar– Tsimerman–Wang–Matchett Wood, [*Remarks on the disproof of the unit distance conjecture*](https://arxiv.org/abs/2605.20695) (2026). An explicit bound is given by Sawin, [*An explicit lower bound for the unit distance problem*](https://arxiv.org/abs/2605.20579) (2026); see erdos_90.variants.sawin_explicit below.
∃ c > 0, {n | ↑n ^ (1 + c) ≤ ↑(Erdos90.maxUnitDistances n)}.InfiniteSolvedStatement only, no proof