{ "domain": "mathematics", "topics": [ "combinatorics" ], "type": "proof", "source": { "key": "erdos", "name": "Erdős Problems", "url": "https://www.erdosproblems.com/20", "id": "20", "curator": "Thomas Bloom", "poser": "Paul Erdős and Richard Rado", "status": "open, $1000 prize", "as_of": "2026-10-20", "prize": "$1000", "catalog": "0521c19bbd38" } }