{"id": "c1216", "title": "C1216 — Reconstruct the hidden interior effect of head cancellation", "filename": "C1216.md", "role": "Research action", "step": 1216, "sha256": "0f4151838a1f5d0b767f1be1f72f7d52dd686d8d2885758071a11e21a1ae02a8", "bytes": 1423, "origins": ["C480–C1634/Research_Cycles/C1132_C1431_Recovered/journal.json#C1216"], "download": "/sources/0f4151838a1f5d0b767f1be1f72f7d52dd686d8d2885758071a11e21a1ae02a8.md", "format": "md", "derived": true, "tags": ["Cumulative", "Rounded"], "excerpt": "Which cumulative boundaries move even though the head error is zero?", "content": "# C1216 — Reconstruct the hidden interior effect of head cancellation\n\n## Question\n\nWhich cumulative boundaries move even though the head error is zero?\n\n## Inputs\n\n```json\n{}\n```\n\n## Sources\n\n```json\n[\n  \"C1215\"\n]\n```\n\n## Opened utc\n\n2026-09-28T05:29:12.387992+00:00\n\n## Results\n\n```json\n{\n  \"interior_field\": {\n    \"path\": \"model/whole_genealogy_rounding_interior_field.json\",\n    \"sha256\": \"6d567b190a9b6394b05ca6e81b64f7eefde7f8e2021b4b92f407e75e25fa0c2d\",\n    \"bytes\": 916\n  },\n  \"nonzero_boundaries\": [\n    {\n      \"boundary\": \"Noah\",\n      \"difference_error\": -4\n    },\n    {\n      \"boundary\": \"Shem\",\n      \"difference_error\": -4\n    },\n    {\n      \"boundary\": \"Arphaxad\",\n      \"difference_error\": -4\n    },\n    {\n      \"boundary\": \"Shelah\",\n      \"difference_error\": -2\n    }\n  ]\n}\n```\n\n## Finding\n\nThe head cancellation hides a−4 comparison shift at Noah, Shem and Arphaxad, followed by−2 at Shelah. Adjacent differences recover the three local rounding changes exactly.\n\n## Reassessment\n\nCheck compatibility with separately rounded remaining years and identify the carry change.\n\n## Checks\n\n```json\n{\n  \"head_terminal_zero\": true,\n  \"recurrence\": true,\n  \"nonzero4\": true\n}\n```\n\n## Closed utc\n\n2026-09-28T05:29:12.390524+00:00\n\n## Record provenance\n\nExact record hash: `05c9eb4596a23c5d92a7bf787703c21929e0f1b60b2a915d78004a7236b807d1`\n\nSource journal: `Research_Cycles/C1132_C1431_Recovered/journal.json`", "journalDownload": "/sources/6adb632ce171623c2bce60d7ed58ae319ccb379cf76b751c0a477c1742fd348c.json", "evidenceLinks": [{"id": "d-6d567b190a9b6394", "title": "model/whole_genealogy_rounding_interior_field.json"}]}