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 "provenance": {
  "authors": [
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  "model": "Claude Opus 5",
  "novelty": "known_parameters",
  "origin": "submission",
  "date": "2026-09-22",
  "construction": "Check deletion from the board entry [[41,19,3]] (codes/41-19-3.json): rows [4, 7] of H_X removed. Dropping two independent stabiliser generators frees two logical qubits and cannot raise the distance.",
  "notes": "Found by sweeping every single-row deletion of every small board entry and keeping those that land undominated. The parent's remaining checks are unchanged."
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 "family": "check-deletion"
}