# C270 evidence packet

Completed 24 September 2026. Continues the existing 490d Unified Chronology research after C269.

Read `490d_C270_SP_Seasonal_Counterpart_of_LXX_Bracket_20260924.md`, then `490d_Mirror_Checkpoint_After_C270_20260924.md`. C271 is proposed, not executed.

## Reproduce the calculation

From this directory, using Python 3 and its standard library:

```sh
python evidence/check_c270.py --output /tmp/490d_c270_replay
```

The verifier uses ten frozen inputs in `sources/`, listed with sizes and SHA-256 values in `SOURCE_MANIFEST.json`. It passes 111 assertions and writes six files:

- `INDUCED_MAPS.json`: inherited correspondence and derived branch maps.
- `COMPONENT_LEDGER.json`: all four cumulative, original regular, reflected regular and local phases.
- `TRANSPORT_CERTIFICATE.json`: branch identities, local reflection and inherited intermediate member.
- `LIMITS_AND_SPANS.json`: bilateral spans and excluded common affine center fit.
- `RESULTS.json`: assertion ledger and bounded conclusion.
- `COMPONENT_LEDGER.csv`: compact source-phase table.

`REPLAY.json` records byte-identical reproduction of all six files in separate main and independent-review output directories. The authored report and checkpoint are not replay outputs. Independent mathematical, source-phase and final reviews are in `evidence/`.

## Integrity and scope

`SCOPE.json` records the finite domain. `CONTROL_INTEGRITY.json` records unchanged original inputs, the 208-node/382-duration-edge C127 graph and the C265 certificate at publication. Absolute original paths are provenance references; they are not required for reproduction elsewhere.

`CERTIFICATE.json` links to C269 and binds the report, checkpoint, source manifest, results, replay and control-integrity record. `ARTIFACT_MANIFEST.json` inventories every other payload, including the certificate, while excluding itself to avoid a circular hash. The certificate does not hash itself or the artifact manifest.

The regular SP counterpart is a dependent transport through inherited source maps. The Noah shift is 3703=7×529; this follows from 17K−10K and is not a new independent witness. No canonical source or graph was edited, earlier campaign rerun, broader Gear comparison executed, or new historical event search performed. Regular Gears remain Noah/Shem/Flood only. C271 remains unexecuted.