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      "after": "2026-09-09",
      "requires_resolution_review": false
    },
    {
      "problem_number": 83,
      "problem_url": "https://www.erdosproblems.com/83",
      "change_class": "formal_solution_metadata",
      "field": "formal_solution_state",
      "before": "unformalized",
      "after": "Lean",
      "requires_resolution_review": false
    },
    {
      "problem_number": 83,
      "problem_url": "https://www.erdosproblems.com/83",
      "change_class": "formal_solution_metadata",
      "field": "formal_solution_last_update",
      "before": null,
      "after": "2026-08-24",
      "requires_resolution_review": false
    },
    {
      "problem_number": 83,
      "problem_url": "https://www.erdosproblems.com/83",
      "change_class": "catalogue_maintenance",
      "field": "derived_status",
      "before": "proved",
      "after": "proved (Lean)",
      "requires_resolution_review": false
    },
    {
      "problem_number": 83,
      "problem_url": "https://www.erdosproblems.com/83",
      "change_class": "statement_formalization_metadata",
      "field": "statement_formalized",
      "before": false,
      "after": true,
      "requires_resolution_review": false
    },
    {
      "problem_number": 83,
      "problem_url": "https://www.erdosproblems.com/83",
      "change_class": "statement_formalization_metadata",
      "field": "statement_formalized_last_update",
      "before": "2025-08-31",
      "after": "2026-09-19",
      "requires_resolution_review": false
    },
    {
      "problem_number": 84,
      "problem_url": "https://www.erdosproblems.com/84",
      "change_class": "catalogue_metadata",
      "field": "oeis",
      "before": [
        "possible"
      ],
      "after": [
        "A399654"
      ],
      "requires_resolution_review": false
    },
    {
      "problem_number": 85,
      "problem_url": "https://www.erdosproblems.com/85",
      "change_class": "catalogue_metadata",
      "field": "tags",
      "before": [
        "graph theory"
      ],
      "after": [
        "graph theory",
        "ramsey theory"
      ],
      "requires_resolution_review": false
    },
    {
      "problem_number": 86,
      "problem_url": "https://www.erdosproblems.com/86",
      "change_class": "statement_formalization_metadata",
      "field": "statement_formalized",
      "before": false,
      "after": true,
      "requires_resolution_review": false
    },
    {
      "problem_number": 86,
      "problem_url": "https://www.erdosproblems.com/86",
      "change_class": "statement_formalization_metadata",
      "field": "statement_formalized_last_update",
      "before": "2025-08-31",
      "after": "2026-09-07",
      "requires_resolution_review": false
    },
    {
      "problem_number": 87,
      "problem_url": "https://www.erdosproblems.com/87",
      "change_class": "statement_formalization_metadata",
      "field": "statement_formalized",
      "before": false,
      "after": true,
      "requires_resolution_review": false
    },
    {
      "problem_number": 87,
      "problem_url": "https://www.erdosproblems.com/87",
      "change_class": "statement_formalization_metadata",
      "field": "statement_formalized_last_update",
      "before": "2025-08-31",
      "after": "2026-09-09",
      "requires_resolution_review": false
    },
    {
      "problem_number": 95,
      "problem_url": "https://www.erdosproblems.com/95",
      "change_class": "formal_solution_metadata",
      "field": "formal_solution_state",
      "before": "unformalized",
      "after": "Lean",
      "requires_resolution_review": false
    },
    {
      "problem_number": 95,
      "problem_url": "https://www.erdosproblems.com/95",
      "change_class": "formal_solution_metadata",
      "field": "formal_solution_last_update",
      "before": null,
      "after": "2026-08-24",
      "requires_resolution_review": false
    },
    {
      "problem_number": 95,
      "problem_url": "https://www.erdosproblems.com/95",
      "change_class": "catalogue_maintenance",
      "field": "derived_status",
      "before": "proved",
      "after": "proved (Lean)",
      "requires_resolution_review": false
    },
    {
      "problem_number": 95,
      "problem_url": "https://www.erdosproblems.com/95",
      "change_class": "statement_formalization_metadata",
      "field": "statement_formalized",
      "before": false,
      "after": true,
      "requires_resolution_review": false
    },
    {
      "problem_number": 95,
      "problem_url": "https://www.erdosproblems.com/95",
      "change_class": "statement_formalization_metadata",
      "field": "statement_formalized_last_update",
      "before": "2025-08-31",
      "after": "2026-09-20",
      "requires_resolution_review": false
    }
  ],
  "summary": {
    "total_changes": 96,
    "candidate_resolution_changes": 2,
    "status_review_changes": 2,
    "metadata_only_changes": 94
  },
  "note": "These are upstream differences from the frozen baseline. They are not resolution events. Candidate status changes require primary-source and verification-date review."
}