C203 — The half-year center residual is consistent in both components
23 September 2026 · Step 48 of 50, continuing C155.
Theδ/2 center gaps hold separately for both seasonal components. The midpoint of corresponding t endpoints is μ−¼; that of the n endpoints is μ+¼. Subtracting corresponding component midpoints leaves the same868+δ/2 and190+δ/2 gaps.
Both17K diagonals have odd whole-year widths and half-integer center values in the selected signed-base coordinates. Whenδ is odd, the13K−δ interval has even width and an integer center. P6's868.5/190.5 gaps follow directly from that parity difference.
No source date is shifted by half a year, and no new fractional Gear is inferred. These are midpoint calculations on the existing paired endpoints, not replacements for the author's3.5-year calendar boundaries. The exact phase check therefore supports the geometric interpretation without changing its source status.
Evidence and scope
K=529. Positive BC base B denotes (B+1)t/Bn BC; reflected AD base A denotes AD At/(A+1)n. Their same-season civil span is B+A, after the no-year-zero correction. AD source projections are not historical AD occurrences. Generated coordinates and interval midpoints do not acquire event identity from numerical coincidence.
Regular Gears remain confined to Noah/Shem/Flood. Creation and Conquest use fixed source-field members; no fourth Gear is admitted. File_18/File_09 and the C127 graph are unchanged. C133–C155 source corrections remain controlling, with the C10 ancestry of the next-Flood-Gear rule now explicit. No historical campaign is rerun, no quarantined primer is reopened, and no N01/N03 expansion or missing Shem join is repaired. Original Reports 01–10 remain previously verified; interrupted original Reports 11–25 remain unestablished.
Sources: controlling File_18 §§2–3, 6A–6D; File_09 paired Mirror rules; selectively retained C05, C08, C10, C123, C128 and C133–C155 evidence. Specific dependencies are named in the body/certificate. 109 assertions passed; see RESULTS.json and CERTIFICATE.json. Assertions, selected field combinations and inherited identities are not independent historical witness counts.