# 490d Mirror checkpoint after C387

24 September 2026. **C387 complete; C388 unexecuted.** 6 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

E/J has eight primary500/100 labelled source squares. Across18 available context/mode tests, ten vertical E edges fail by25/23,2,or71/23 while every horizontal Shem J edge remains exact. Six Gear0 requests remain unavailable. No valid source mode is rejected.



## Retained context

C383 is the latest preceding synthesis. The complete frozen Flood-pivot common-P/J census has six cumulative signed-minus-two and four regular signed-plus-two source quadruples. Two regular lower-full430 contexts are minus215 translations; only original full430 i3/i5 joins retain17K. P/J moving-pivot squares commute exactly when pivot separationD=230h. Finite paths have at most three cumulative or two regular edges. In translated frames the maps share the existing source input as center; operator counts determine the word map, and distinct counts retain distinct slopes. Paired iteration raises cross-spans by4, so it does not preserve17K. Fixed-pivot order defect is±20/897. J300/299 is File02 gap conversion, not calendar Residue Protocol. C373 is the latest preceding synthesis. At source Flood pivots 460 apart, P=70/69 on 138→140 and J=300/299 on 598→600 reach the same existing two-year repair. All four complete cumulative rows and regular primary i3/i5 pass; companion regular rows fail. Twenty C319 controls leave 22:i3/i5 conditionally. Equal integer gains have family69m→70m,299m→300m,pivot230m, source-qualified side529m; actual460 fixesm2. The pairing is not a reviewed source prescription or a global map. Same-offset comparisons pass; fixed-pivot phase transport fails. Native cumulative Noah950 translates by existing19K to reflectedSP950 with birth/death roles exchanged. The full source bridge matrix has primary69/138 and companion70/140 remainders; the companion459 includes an explicit annual-index difference. The cumulative joined500/1100 comparison has no source support in its frozen menu. C373 retains all earlier qualifications. C363 is an earlier 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

86 main checks and 16 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

C388: Compose the admitted E/J squares across their complete two-edge regular source paths. Check whole-map equality, distinguish it from endpoint agreement of the other P/J words, and locate the actual Gear and E-iteration boundaries.

The source and mode qualification is now explicit. The next bounded question is whether the surviving squares form a finite compatible strip, rather than isolated endpoint coincidences.

Continue within the authorized batch, reassessing after the next completed result.