{"id": "c902", "title": "C902 — Recover whole source-pair families from span and placement", "filename": "C902.md", "role": "Research action", "step": 902, "sha256": "893a6ebb965379ae3baf5ea4cbfc0ca7ad7139bfab7a822031b0735488045998", "bytes": 1652, "origins": ["C480–C1634/Research_Cycles/C0832_C0931/journal.json#C902"], "download": "/sources/893a6ebb965379ae3baf5ea4cbfc0ca7ad7139bfab7a822031b0735488045998.md", "format": "md", "derived": true, "tags": ["Rounded"], "excerpt": "Does the endpoint-coordinate basis reconstruct all supplied pairs exactly?", "content": "# C902 — Recover whole source-pair families from span and placement\n\n## Question\n\nDoes the endpoint-coordinate basis reconstruct all supplied pairs exactly?\n\n## Inputs\n\n```json\n{}\n```\n\n## Sources\n\n```json\n[\n  \"C892 complete six\",\n  \"C831 Actual/Rounded weighted bridge\"\n]\n```\n\n## Opened utc\n\n2026-09-28T02:54:22.325714+00:00\n\n## Results\n\n```json\n{\n  \"recovery\": {\n    \"path\": \"model/endpoint_basis_recovery.json\",\n    \"sha256\": \"db5f0def0e97416526798219789a2f562c5cecb648b744c5c98d3ed0d1fddf39\",\n    \"bytes\": 1504\n  },\n  \"weighted_rows\": [\n    {\n      \"id\": \"Actual_weighted\",\n      \"lambda\": \"4/5\",\n      \"D\": 9890,\n      \"W\": 12026,\n      \"recovered_C\": 14004,\n      \"recovered_R\": 4114,\n      \"source_C\": 14004,\n      \"source_R\": 4114\n    },\n    {\n      \"id\": \"Rounded_weighted\",\n      \"lambda\": \"4/5\",\n      \"D\": 9900,\n      \"W\": 12026,\n      \"recovered_C\": 14006,\n      \"recovered_R\": 4106,\n      \"source_C\": 14006,\n      \"source_R\": 4106\n    }\n  ]\n}\n```\n\n## Finding\n\nAll six macro pairs and both weighted Creation pairs are recovered exactly. The Actual and Rounded weighted coordinates both equal12026, but their different spans9890 and9900 recover different original pairs. A shared coordinate alone does not merge them.\n\n## Reassessment\n\nCompare whole-frame motion with source-fixed anchor changes across the new modules.\n\n## Checks\n\n```json\n{\n  \"all_recovered\": true,\n  \"weighted_equal\": true,\n  \"spans_differ\": true\n}\n```\n\n## Closed utc\n\n2026-09-28T02:54:22.326480+00:00\n\n## Record provenance\n\nExact record hash: `00cc4f983c89c77c16600c84caed260c23465fa6481502c83b6451e0565a0c31`\n\nSource journal: `Research_Cycles/C0832_C0931/journal.json`", "journalDownload": "/sources/6a37be4e218f9f467cbde5e9db3723ce9c79dc78cc97d1a289422b96cb9971e0.json", "evidenceLinks": [{"id": "d-db5f0def0e974165", "title": "model/endpoint_basis_recovery.json"}]}