# Independent review: C850–C858

**Result: PASS.** The completed File52c paired-anchor reconstruction and algebraic branch coverage agree with the frozen primary source. No correction to a completed record, script or model is required.

The review independently parsed §2.1 and Appendices A.2–A.3 of `evidence/sources/File52c_latest.md`, whose SHA256 is `a5ea84562101158b60d0cf296765d6eff38e7a2abda4e74ad1b353dfd13b9530`. It compared every source name, date, selected anchor and endpoint against the completed model. It reconstructed the endpoints with integer division/remainder arithmetic, independently of both the preparation's string implementation and C852's digit-vector check.

All 32 source rows and all 64 original endpoints match. All 32 gain identities and paired differences match. The branch partition is complete and disjoint: 14 long-core rows, 16 shortened-core rows and the two retained-zero rows. These quantities describe verification coverage; no target-frequency analysis was performed.

For the long-core rows, subtracting 140 from `n=(D−a0)/10` preserves the units digit and forces either the +990 or +1980 endpoint gap. Every shortened-core row satisfies its stated three-to-two or three-to-one positional formula. Adam's retained-placeholder routes produce a 7200 gap; Jacob's produce zero. These results account for the whole manifest without exceptions added to the operation.

The affine obstruction is exact. Seth and Enosh force slope 1 and intercept 990 between the two endpoint columns; this predicts 4226 for Lamech while his literal Conquest endpoint is 5216. The positive explanation is the digit-register field, not a repaired affine map.

Script inspection found one `inv` call in C850–C858, in C852, whose argument is the original local `duration = source_BC − anchor`. No generated inverse endpoint is submitted to reversal. No target columns or new statistical tally enter the reviewed calculations. C851 was reviewed as the intervening twenty-step checkpoint and scope transition, rather than as a new independent audit of the preceding File58 family.

No substantive overclaim was found. Preserve two qualifications in subsequent exposition: the branch formulas have the stated digit domains and cover this fixed manifest; the reconstruction explains arithmetic route dependence without explaining the historical selection of the original chronological digits. C858 already retains both limits through its source-bound domain and explicit unexplained premise.

Evidence: `INDEPENDENT_C850_C858.json` records 14 passing checks, the complete independently reconstructed field, the single-pass call inspection and hashes of reviewed sources, scripts and models. Reproduction script: `prep/independent_review_C850_C858.py`. No completed root artifact was modified.