Erdős Problem 505 (disproved). Borsuk's conjecture is false for sufficiently large $n$: there exists a dimension $n$ and a bounded set $S \subseteq \mathbb{R}^n$ with positive diameter such that $S$ cannot be covered by $n + 1$ subsets each of diameter strictly less than $\operatorname{diam}(S)$.

How a contribution reaches this record

Seven steps, in four places.

1. 1

   Read the sources and their formal declarations.

   Public
2. 2

   Work on it, wherever you work.

   Your machine
3. 3

   Keep an Approach and its Attempts here.

   Needs an account
4. 4

   Attach evidence by its content root.

   Needs an account
5. 5

   Prepare an unsigned Submission draft.

   Needs an account
6. 6

   Sign it with your own key.

   Your machine
7. 7

   The Repository decides.

   The Repository