What's this about?
The project formally proves the smallest square that can contain eleven non-overlapping unit squares, even when they rotate. Its verification run accepted 7,920 Lean modules with zero unproved placeholders.
What exactly is a native numerical certificate?
Hard numerical cases are computed by compiled code and checked against precisely recorded inputs. The trust base therefore includes Lean's kernel and native compiler, not just the kernel alone.
What's the community saying?
HN 109 points and 52 comments.
- Readers wanted diagrams because the final irregular packing is hard to understand from formulas alone.
- Formal-methods practitioners discussed the difficulty of interval arithmetic and trustworthy rounding.
- Commenters distinguished discovering a candidate arrangement from proving no smaller arrangement can work.