Erdős unit distance problem: Square grid vs OpenAI construction

The Erdős unit distance problem asks a child-simple, mathematician-hard question: if you place n points on a flat plane, how many pairs can be exactly one unit apart? The Square grid gives the natural baseline: almost 2n unit links. The OpenAI construction proves that this baseline is not the right long-run intuition: for infinitely many huge values of n, there are point sets with at least n1+δ unit links for a fixed δ > 0.

Log scale. Counts use the full n. The picture draws only a representative patch so the page stays fast.
current view
OpenAI construction
point Square grid link OpenAI construction link

What the proof actually does

1

Make hidden switches

Use algebraic number theory to create many independent choices that act like hidden switches.

2

Keep compatible choices

A class-group argument keeps many choices that can be combined into the same kind of object.

3

Create unit moves

Each compatible choice creates a move whose length is exactly 1 in every relevant complex view.

4

Pack many points

Put many lattice points inside a high-dimensional rounded box so many point-plus-move pairs remain inside.

5

Project to the plane

Look at one complex coordinate. Each surviving hidden move becomes a one-unit segment in the plane.

This page follows the proof skeleton, but the plotted dots are a browser cartoon. The actual construction needs explicit high-degree number fields, class groups, prime ideals, embeddings, and a lattice coset obtained by an averaging argument. See the proof PDF and the human-readable remarks for the real construction.

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Useful links

OpenAI announcement

The accessible overview of the result and why it matters.

Planar Point Sets with Many Unit Distances

The proof document with the theorem and construction.

Remarks on the disproof

A digested, human-verified discussion of the counterexample and its mathematical context.

MathWorld: Erdős unit distance problem

A short reference definition of the problem.

Erdős Problems #90

Problem-history page with known bounds and Erdős’s prize framing.

Unit distance exponent

Terence Tao’s optimization-problems page summarizing exponent bounds.

Scientific American explainer

A readable news explanation of the breakthrough.

Gil Kalai commentary

Mathematician commentary and links around the result.