Problem dossier · Geometry & Packing

Borsuk's problem in low dimensions

Can every bounded set of diameter 1 in R^d be partitioned into d + 1 pieces of strictly smaller diameter?

§1

Status

True for d ≤ 3, false for d ≥ 64 (Kahn–Kalai-style counterexamples, refined since); every dimension from 4 to 63 is open.

Think you can crack this one? Read the playbook before you announce →
§2

The Angle of Attack

Explore candidate counterexample constructions (two-distance sets, strongly regular graph geometries) in moderate dimensions; build partition certificates for concrete bodies in R^3–R^4.

Tags: diameter · partitions · convex geometry · counterexample

§3

The Lab

No instruments built yet. When this problem gets tackled, its interactive instruments — explorers, searches, verifiers running in the browser — live here. See the Collatz dossier for what a fully tackled problem looks like.
§4

The Log

Empty. Work on this problem gets logged here as dated entries — constructions tried, code run, dead ends included. Dead ends are results.
§5

Related Problems

More open problems in Geometry & Packing and adjacent territory.