# 490d Mirror checkpoint after C373

24 September 2026. **C373 complete; C374 unexecuted.** 0 steps remain in the current authorization. Read this checkpoint and report first; frozen predecessor records retain earlier findings. Current decisions override stale archive instructions. Do not repeat completed research.

## Current result

C364–C373 complete. The cumulative joined460/598→500/600 proposal has no source internal or terminal member in its frozen menu. Existing cumulative and regular Noah950 biographies instead share460/490/460 source shapes; companion shapes require the explicit annual-member shift j=k−1 and retain459/491/459. Fixed19K carries the native cumulative Noah lifespan to the reflected SP lifespan with birth/death roles exchanged and same-offset components preserved, but does not carry the OFF interior. The full bridge matrix has primary remainders69/138 and companion70/140 after division by529. At actual Flood pivots460 apart, P70/69 on138→140 and J300/299 on598→600 reach the same existing two-year repair: all four complete cumulative rows and the two regular primary rows pass; companion regular rows fail. The full C319 comparison again leaves22:i3/i5. Equal integer gains have primitive family69m→70m,299m→300m,separation230m. When the sourced first segment equals that separation, the side is529m; the actual460 fixesm2 and recovers1058=2K. This is a conditional source-supported arithmetic explanation, not a textual rule coupling the ratios or a global map. No canonical or graph edits.

Latest completed C373; C374 unexecuted and outside the completed authorization. Use the C373 compact kit as active packet, starting with synthesis/checkpoint; earlier archives are selective references. C370 supplies paired P/J endpoint records; C371 contains uniqueness, twenty-control, boundary and phase tests; C372 gives the primitive integer proof. Retain C367 native950 transport by19K with exchanged birth/death roles. C369 bridge matrices use d460 primary and d459 companion, the latter explicitly including annual-index ancestry;69/70 remainders are not calendar residues. For D460, anchored P and J agree uniquely at outer gap598 with output600 and inner138→140; same-offset component comparisons pass, fixed-center pivot maps do not carry both inherited phases. The equal-gain integer family has pivot230m and source-qualified side529m; no primitive230 source endpoint is adopted. The regular companion alternative SP start allows a P-only hit while J still misses; never merge event boundaries. Prior C353458+600 repairs and their2K/17K outer endpoints remain. Prior C363 regular joined460/598→500/600 and Shem-held squared-E1058→1250 remain separately qualified; the cumulative joined counterpart has no source500 or1100 span in the declared menu. C343 Noah-held1058→1150→1250 ladder remains retained. C287 completei2…5 and C319 slicei3…7 differ. Source500/100 and502/98 modes remain valid. K529,E25/23,P70/69; File02 gapJ300/299 is not ResidueProtocol. Global paired MirrorJanuaryAD1, local junctionJanuaryAD2, no civil yearzero. Regular GearsNoah/Shem/Flood only; SP minus-one person companions local; primary Noah death retains inclusive/harmonic qualification. No new source endpoints, phases, fitted anchors, global axes, upstream Gears, primers, canonical or graph edits. Corrected LXX8464 supplement remains awareness only:1564→1700,2484→2700,920→1000; AD3746/2300 superseded. Original unprefixed reports, Engine reports and C-series remain distinct; the old incompleteSeptember17 ZIP differs from the later verified intact original. No independent witness count or source-prescribed selector follows from repeated algebra or coordinates.

## Retained context

C363 is the latest preceding synthesis. Joined460/598→500/600 reaches sourced SP Shem birth/death and changes one original17K span by42;550/529 is diagnostic only. The source Shem600+50+600 rectangle gives1250; Shem-held squaredE maps1058→1250 but has no admitted2056/2058 intermediate. Both new constructions leave02/22:i3/i5, with cumulativea unselected. Phase ancestry and source membership remain explicit. C353 adds the primary458+600=1058 paired source realization with original2K/17K outer endpoints unchanged, the598→650 SP/MT Shem image under E, and bounded partial relations.600 output alone leaves nine primary controls; both598 inputs select22 conditionally. Whole-affine gap conversion is not biography or seasonal-component transport. C343 is the earlier source-ladder synthesis. The primary Noah-held source ladder1058→1150→1250 under E=25/23 has refinement460+490+108+92+100. Companion actual MT Shem gives1149 and the valid502/98 mode gives1152; both retain double-E outer endpoints. C341 distinguishes component-preserving comparisons from one physical-time affine dilation or a biography-preserving map. C334 shared Shem±2 origin is explicit, but exact cumulative/regular endpoint coupling is unestablished in reviewed passages. C342 full regular ladder leaves C319 controls02 and22 at i3/i5; separate17K selects22. C287 full SP domaini2…5 remains; C319 is onlyi3…7. C314 reversal requiresi+j=10 with opposite cumulative ancestry phase; C323 conditionali=j5 uses its extra support requirements. SP primary death retains inclusive/harmonic qualification; matched lifespan950 remains. Source500/100 and502/98 bindings are valid alternatives. Scalar/C89 prior art remains distinct from the Noah-held endpoint realization. Corrected LXX8464 supplement is awareness only:1564→1700,2484→2700,920→1000; AD3746/2300 superseded. Earlier incompleteSeptember17 ZIP differs from the later verified intact original. Original unprefixed reports, Engine reports and C-series remain distinct. No independent witness or source-prescribed selector is inferred from repeated coordinates.

Mirror/529 focus: K=529, E=25/23, P=70/69. Global paired Mirror January AD1; local junction January AD2; no civil year zero. Regular Gears are Noah/Shem/Flood only. SP minus-one person companions remain local to SP Noah/Shem; Flood close is a separate boundary. No upstream/cumulative Gear, new endpoint or phase, fitted anchor, global axis, primer reopening, canonical or graph edit. Capture now; canonize later. Source identity, context, modal binding, generated coordinates and phase ancestry stay distinct.

## Verification

77 main checks and 63 frozen-input/predecessor authentication checks passed. A second main replay produced byte-identical DATA/RESULTS. These checks and the source interpretation were performed by the root agent; no new independent-agent review is claimed. All frozen originals and standing controls remain unchanged. Verification counts are not independent-witness counts.

## Best next bounded step

C374: Audit the full primary source-labelled Mirror rectangle after both two-year P/J repairs: enumerate the internal and cross-field spans, determine which inherited relationships survive, and test whether a whole-rectangle comparison follows. Hold the original2K/17K outer endpoints and inherited phase ancestry fixed; adopt no fitted bridge, new endpoint or anchor.

The local paired conversions now have source support and exact integer structure. Their compatibility with the complete Mirror configuration is the immediate unresolved question. This proposal is unexecuted; the current authorization ends at C373.

The current authorization ends here. C374 requires a new instruction.