{
  "domain": "physics-astronomy",
  "topics": [
    "mathematical-physics",
    "analysis"
  ],
  "type": "construction",
  "source": {
    "key": "horizonmath",
    "name": "HorizonMath",
    "url": "https://github.com/ewang26/HorizonMath/blob/4ef0b61a8a6d4c5ded661fab7c2e896af84abe6e/data/problems_full.json#L334-L344",
    "id": "feigenbaum_delta",
    "curator": "Erik Y. Wang, Sumeet R. Motwani et al.",
    "status": "open",
    "as_of": "2026-10-20",
    "catalog": "0521c19bbd38"
  }
}