{
  "problem_id": "IMO2026-P4",
  "obligations": [
    {
      "id": "O1",
      "claim": "Normalized cut-state formulas (b,x,q-b-x) and (c,a-x,b+x)",
      "status": "CLAIMED",
      "dependencies": [],
      "load_bearing": true,
      "notes": ""
    },
    {
      "id": "O2",
      "claim": "Integer k in (b,a+b) forces an integer-multiple angle in both branches",
      "status": "CLAIMED",
      "dependencies": [
        "O1"
      ],
      "load_bearing": true,
      "notes": ""
    },
    {
      "id": "O3",
      "claim": "Monovariant m -> m-1 forces m=1 when q integer (Mulan wins)",
      "status": "CLAIMED",
      "dependencies": [
        "O2"
      ],
      "load_bearing": false,
      "notes": ""
    },
    {
      "id": "O4",
      "claim": "Noninteger invariant preserved by >=1 branch when q not integer",
      "status": "CLAIMED",
      "dependencies": [
        "O1"
      ],
      "load_bearing": true,
      "notes": ""
    },
    {
      "id": "O5",
      "claim": "Classification theta = 180/n, n>=2",
      "status": "CLAIMED",
      "dependencies": [
        "O3",
        "O4"
      ],
      "load_bearing": false,
      "notes": ""
    }
  ]
}