The inscribed square problem (Toeplitz's square peg problem)
Show that every simple closed curve in the plane passes through the four vertices of some square.
| 1 | { |
| 2 | "domain": "mathematics", |
| 3 | "topics": [ |
| 4 | "geometry-topology" |
| 5 | ], |
| 6 | "type": "proof", |
| 7 | "cover": { |
| 8 | "motif": "blocks" |
| 9 | }, |
| 10 | "source": { |
| 11 | "key": "formal-conjectures", |
| 12 | "name": "Formal Conjectures", |
| 13 | "url": "https://github.com/google-deepmind/formal-conjectures/blob/main/FormalConjectures/Wikipedia/InscribedSquare.lean", |
| 14 | "id": "Wikipedia/InscribedSquare", |
| 15 | "curator": "Google DeepMind and contributors", |
| 16 | "poser": "Otto Toeplitz", |
| 17 | "status": "open", |
| 18 | "as_of": "2026-10-20", |
| 19 | "catalog": "0521c19bbd38" |
| 20 | } |
| 21 | } |