# 490d Mirror checkpoint after C457

25 September 2026 UTC. **C457 complete; C458 unexecuted.** 12 steps remain in the current authorization. Current decisions override archived next-step text.

## Current result

Complete shared-word closure of all60 sourced529/1058 pairs reaches63 pairs in756 trials. Only two seeds move:1895/2953→1745/2895 and2148/3206→2020/3170, both1058→1150 underE3620. Only the latter continues, to1956/3206 with span1250 underE2756. No reflection or further E step is admitted.

## Earlier results in this batch

**C445**: All 5,968 ordered two-reflection trials give 330 complete paths: 208 zero-shift returns and 122 nonzero paths. Sourced shifts are ±4 (48 each), ±120 (5 each) and ±124 (8 each); both ±116 have zero complete paths.

**C446**: The four-reflection graph has 373 vertices, 106 edges including four loops, and 272 components. Its 152 active coordinates form 49 nontrivial components plus two loop-only singletons; 221 coordinates have no admitted reflection. The largest components have six coordinates and the maximum shortest-path distance is four.

**C447**: No nonzero multiple of 529 occurs among all 191 reflection-reachable coordinate pairs. The nonzero E-path coordinates 2148, 2020 and 1956 are reflection-isolated. The source pivots 3620/2756 share a four-point component; 3206/3170 share a different four-point component; midpoint3188 is a loop-only singleton.

**C448**: The reflection graph has one ordinary simple cycle, 2610→3766→2730→3770→2610, through centers3188,3248,3250,3190. Its four-reflection affine word is the identity because3188+3250=3248+3190. The other four cycles are single-center fixed-point loops, not identity maps.

**C449**: All 8,952 four-distinct-center trials produce exactly eight complete words, all returns: the two directions and four starts of one cycle. Each of the eight identity orders has only one sourced input. The cycle has eight source-label assignments and none keeps one unchanged source context.

**C450**: The eight existing pivots yield37 sourced E arrows in2,984 trials: eight pivot self-arrows and29 distinct nonzero arrows. Another2,854 outputs are fractional and93 are integer coordinates absent from the frozen register.

**C451**: The combined fixed E/reflection graph has245 operator-labelled arrows and522 reachable directed distinct pairs,140 beyond reflection-only reachability. None has a nonzero529-multiple gap. One merged strong component has eight coordinates; all other strong components retain the reflection partition.

**C452**: The only enlarged strong component joins two former reflection components. Its unique simple E-bearing directed cycle is2731→3765→2735→2733→2731. The two E legs each expand a signed−23 pivot gap to−25, moving the Noah-death coordinate down one Gear. The full word fixes2731 with slope625/529 and is not an identity.

**C453**: The residual215−130−60−2=23 generates88 same-role source-label E templates, representing64 distinct coordinate arrows. Five label templates realize three of the four one-Gear arrows at the fixed pivots. The remaining arrow is MTNoah2841→2843 about2818, explained by950−650−215−60−2=23.

**C454**: The frozen register contains60 direct nonzero529-multiple coordinate pairs:34 at529 and26 at1058, with119 labelled source assignments. No pair is connected in either direction by the fixed mixed E/reflection menu. Thus the graph exclusion does not mean the source register lacks529 spans.

**C455**: Across23,872 input/word trials,64 ordered E pairs yield15 complete paths. Thirteen words have a sourced effective fixed point;11 complete paths use one. The only nonzero529-multiple input gap is the established1058 gap atH3206, with2148→2020→1956. Four additional paths have rational, unsourced effective pivots.

**C456**: For integer input and effective pivot, a two-E output is integral exactly when the input gap is divisible by529. The13 sourced-pivot words have17 integer-output cases,15 sourced outputs and11 complete paths. Among nonzero gaps the gates narrow4→2→1; only2148→2020→1956 survives.

## Baseline and standing scope

C444 is the authenticated baseline. Its checkpoint is frozen in sources/C444_CHECKPOINT.md. The fixed local reflection centers are 3188, 3190, 3248 and 3250, each an existing MT Noah birth record. The 528 labelled Noah/Shem/Flood records occupy 373 integer BC coordinates. These local source comparisons do not replace the January-AD1 global Mirror. The only complete forward 2K E path remains 2148→2020→1956. The SKL appendix and corrected LXX8464 observations remain supplemental; no redirection follows. C432’s E excerpt locator was corrected in C444 to File_46 L3, lines117–133; prior arithmetic already used25/23.

Mirror/529 focus: K=529, E=25/23, P=70/69; J=300/299 remains File02 gap conversion, not a calendar date operator or Residue Protocol. Regular Gears are Noah/Shem/Flood only. SP person companions are local to Noah/Shem; Flood close is an independent event boundary. Both500/100 and502/98 bindings remain valid; SP primary Noah death retains its inclusive/harmonic qualification. LXX native Cainan is ON; OFF is theoretical removal. Global paired Mirror January AD1; local junction January AD2; no civil year zero. No new source point, phase, fitted axis, upstream/cumulative Gear, primer reopening or canonical/graph edit. Capture now; canonize later. Coordinates, source labels, context aliases and derived comparisons remain distinct. Counts are not independent historical witnesses.

## Limits and verification

Both ladders are comparisons of distinct source contexts. The interval closure adds no anchors, graph edges to the canonical chronology, or evidence of historical intent.

3 calculation checks and 21 source/predecessor authentication checks passed. Main result files replay byte for byte. These are root-agent checks, not an independent-agent review or independent historical witnesses.

## Best next bounded step

C458: Resolve all endpoints and pivots of the two admitted interval ladders into their source-state terms and derive the1058,1150 and1250 gaps directly from the Noah/Shem/Flood bases.

The shared-word test identifies a positive source-complete interval structure. Its two seeds and all resulting gaps should now be derived from source terms rather than reported only as coordinates.

Continue within the authorized batch and reassess after the next result.