{"id": "c491", "title": "C491 — Close the cross-tradition source explanation", "filename": "C491.md", "role": "Research action", "step": 491, "sha256": "10d017eaa864dcbdad0c79fc3f5c764566b231ce5daebe3a9c03cf4d37d86d9d", "bytes": 1446, "origins": ["C480–C1634/Research_Cycles/C0482_C0531/journal.json#C491"], "download": "/sources/10d017eaa864dcbdad0c79fc3f5c764566b231ce5daebe3a9c03cf4d37d86d9d.md", "format": "md", "derived": true, "tags": ["Regular", "Cumulative", "Rounded"], "excerpt": "Can every unit of LXX’s cumulative890 difference be traced to supplied lifespan rows?", "content": "# C491 — Close the cross-tradition source explanation\n\n## Question\n\nCan every unit of LXX’s cumulative890 difference be traced to supplied lifespan rows?\n\n## Inputs\n\n```json\n{\n  \"Lamech\": -24,\n  \"Arphaxad\": 27,\n  \"Cainan\": 460,\n  \"Shelah\": 27,\n  \"Eber\": 40,\n  \"Peleg\": 100,\n  \"Reu\": 100,\n  \"Serug\": 100,\n  \"Nahor\": 60\n}\n```\n\n## Sources\n\n```json\n[\n  \"File18 §§2.2,4.1–4.2,6D; corrected339/339/330 triplet\"\n]\n```\n\n## Opened utc\n\n2026-09-27T22:40:15.843136+00:00\n\n## Results\n\n```json\n{\n  \"row_deltas\": {\n    \"Lamech\": -24,\n    \"Arphaxad\": 27,\n    \"Cainan\": 460,\n    \"Shelah\": 27,\n    \"Eber\": 40,\n    \"Peleg\": 100,\n    \"Reu\": 100,\n    \"Serug\": 100,\n    \"Nahor\": 60\n  },\n  \"postFlood_without_Cainan\": 454,\n  \"all_deltas\": 890,\n  \"endpoint_check\": 890\n}\n```\n\n## Finding\n\nThe total is454+460−24=890. Alongside SP’s−608, this completes a source-row explanation of why the regular and cumulative families move differently. A common projection grammar is supported; a common12026 endpoint is not.\n\n## Reassessment\n\nReturn to the MT rounded/actual interface and derive its residual conservation from rows and endpoint selections.\n\n## Checks\n\n```json\n{\n  \"total\": true,\n  \"postFlood\": true,\n  \"regular_independent\": true\n}\n```\n\n## Closed utc\n\n2026-09-27T22:40:15.843363+00:00\n\n## Record provenance\n\nExact record hash: `09851060f453b478462087352850941d9c1e72097fcda695304666ec74bf6567`\n\nSource journal: `Research_Cycles/C0482_C0531/journal.json`", "journalDownload": "/sources/6eaeccad4734eff2f6ac20ba847967877b944f9758c53c712ac8b5be2ddf61eb.json", "evidenceLinks": [{"id": "d-68301ab760bfbe2e", "title": "File 18"}]}