# C209 — The two right-endpoint midpoints have unequal source status

23 September 2026 · Step 4 of 60, continuing C205.

The first midpoint is a retained SP companion Noah-death reflection. Its image under the same Creation-anchored map is not a retained Noah/Shem/Flood event in the 48-row C01 register.

| Chain index | Midpoint of Flood–MT Noah | Midpoint of MT–SP Noah | Status |
|---|---|---|---|
| 3 | 2757 | 3381 | source / generated |
| 5 | 2759 | 3383 | source / generated |

The map preserves the midpoint equation exactly, but does not preserve the named-event status of that midpoint. The negative conclusion is limited to this held regular event register; it does not assert that 3381 or 3383 is absent from every chronological construction.

## Evidence and scope

K=529 and r=25/23. BC base B means (B+1)t/Bn BC; reflected AD base A means AD At/(A+1)n. Their civil span is B+A in both seasonal components, with no year zero. Signed paired centers are −B and +A; the center model uses components ±1/4 and restores this separation after dilation. An interval center is geometry, not an event or a proposed universal Mirror axis.

Regular Gears are restricted to Noah/Shem/Flood. Creation and Conquest retain fixed source-field members; no fourth Gear is admitted. Generated coordinates, source-field membership and stored graph incidence are distinct. File_18/File_09 and the frozen C127 graph are unchanged. Earlier N01/N03 qualifications, the missing Shem join, closed primers and unestablished original Reports 11–25 remain unchanged. This packet selectively uses prior evidence; it does not rerun completed campaigns. Assertions and alternative placements are not independent historical witness counts.

**6 step-specific checks and 19 frozen-input checks passed.** Exact inputs, results and predecessor hashes are in the accompanying JSON records; calculation code is in the evidence archive. Source dependencies are identified in the body and frozen in `sources/`.