{"id": "c869", "title": "C869 — Recover the whole49/70 common coarsening", "filename": "C869.md", "role": "Research action", "step": 869, "sha256": "5fa45a5e6fb404c02a27b2a59738725c1155399adfcc928af0a33a894475e1df", "bytes": 1342, "origins": ["C480–C1634/Research_Cycles/C0832_C0931/journal.json#C869"], "download": "/sources/5fa45a5e6fb404c02a27b2a59738725c1155399adfcc928af0a33a894475e1df.md", "format": "md", "derived": true, "tags": [], "excerpt": "How do the two measurements divide one primary5390-year display?", "content": "# C869 — Recover the whole49/70 common coarsening\n\n## Question\n\nHow do the two measurements divide one primary5390-year display?\n\n## Inputs\n\n```json\n{\n  \"span\": 5390,\n  \"units\": [\n    49,\n    70\n  ]\n}\n```\n\n## Sources\n\n```json\n[\n  \"File54 §§8.6,13.2\",\n  \"C860\"\n]\n```\n\n## Opened utc\n\n2026-09-28T02:45:07.563470+00:00\n\n## Results\n\n```json\n{\n  \"unit\": 490,\n  \"boundaries\": {\n    \"path\": \"model/NT_49_70_coarsening.json\",\n    \"sha256\": \"0f8f6b632e788373b74ddac612833439ab7771d12b0a72baef53e4076e4974ee\",\n    \"bytes\": 959\n  },\n  \"partition_common_blocks\": [\n    3,\n    5,\n    3\n  ],\n  \"partition_70_slots\": [\n    21,\n    35,\n    21\n  ],\n  \"partition_49_units\": [\n    30,\n    50,\n    30\n  ]\n}\n```\n\n## Finding\n\n70k=49j holds exactly at k7m,j10m. The whole primary span has12 common boundaries in490-year steps; the source1470|2450|1470 partition becomes3|5|3 blocks in either measurement. The extended49-grid is a comparison construction.\n\n## Reassessment\n\nTest reflection on the complete common grid and its source-marked partition.\n\n## Checks\n\n```json\n{\n  \"whole_span\": true,\n  \"literal_field\": true,\n  \"partition\": true\n}\n```\n\n## Closed utc\n\n2026-09-28T02:45:07.565774+00:00\n\n## Record provenance\n\nExact record hash: `efff108af7686541b55686e404c8464619509f11f66b6e1b153a64d1cc9470be`\n\nSource journal: `Research_Cycles/C0832_C0931/journal.json`", "journalDownload": "/sources/6a37be4e218f9f467cbde5e9db3723ce9c79dc78cc97d1a289422b96cb9971e0.json", "evidenceLinks": [{"id": "d-0f8f6b632e788373", "title": "model/NT_49_70_coarsening.json"}, {"id": "d-1ff1914fa180de2a", "title": "File 54"}]}