C258 — The selected 6875 interval lies 191 years before the SP 17-fold center

23 September 2026 · Step 53 of 60, continuing C205.

Across all six rows, the center of the 6875 Creation-to-Flood interval is 191 years earlier than the enclosing SP 17-fold center. The unequal outer flanks are 868 and 1250, giving (1250−868)/2=191.

C201 already expresses this value as the δ=2 case of its center grammar. The new result is a source selector for that case: the twice-expanded native 11-fold family. The 191 value is therefore integrated as a dependent geometric consequence, not newly counted as an independent numerical witness.

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.

12 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/.