Independent SCC placement result review

Source4dd764fa, primary run scc-placement-20260925/run01. Read-only recorded-result audit; no compiler, router, native or engine execution. The structural hypothesis succeeds strongly on sparse40, but this candidate is not adoptable. One compound case is rejected, several successful cases regress labels/sharing or area, and no native tracing acceptance exists.

Admission and independent scope

Verified all bound input hashes against receipt, before/after binding equality, eight child exits0/not timed out, recorded stdout/stderr hashes, and exact released-router-control bytes. All14 candidate cases are accounted for:13 supported, one explicit failure. Parent separately owns full Project conservation; this review does not substitute geometric metrics for that check.

The standalone script reconstructs sibling-quotient directed edges from original projected nodes/edges, computes mutual reachability independently, verifies every reported SCC membership and condensation rank ordering, and measures final component extents. These checks pass for all13 supported cases. It also checks each perimeter walk contains exactly the component membership once. It does not claim that DFS order is an optimal cycle traversal.

Independent grouped collinear sweeps cover all available original/reset/old-layered/candidate scenes. Each sweep splits segments at interval endpoints and retains both distinct-edge physical sharing and raw segment-pair multiplicity. Raw multiplicity agrees with all emitted shared-length totals within0.001. Initial edge-deduplicated comparison exposed a folded route retrace, explained below; both definitions and the initial output are preserved. Candidate repeat-input equality, nine subsequent calls and both roundtrips report exact equality for all13 successes; no independently rerun semantic/history test is claimed.

Complete outcomes

Sharing columns are reset / old layered / SCC, raw pairwise segment units.

Case	Sharing	Result
flat_chain_4	0 /0 /0	Successful, fewer area units than reset, no recorded collision/warning.
chain_7_row_wrap	0 /0 /0	Successful; area523584→278256.
diamond	36 /82 /36	Restores reset sharing; no crossing.
crossed_bipartite	276 /344 /368	Worse sharing than both controls despite smaller area; no crossing.
nested_cross_boundary	0 /0 /0	Label/node1→0, area284096→455366.
authored_detour_and_label	0 /0 /0	Successful; reset semantics audited separately by parent.
fixed_ports	0 /0 /0	Successful, smaller area; anchor conservation separate.
two_containers_reversed_children	control retained /old retained /failed	Explicit “Final Rust projection differs from intended node geometry”; no candidate metrics or success inferred.
long_ordinary_labels	36 /36 /36	Label/node2→0, modest area growth.
workshop_sa_original	1832 /1467 /344	Sharing/contact gains; label/node1→3, label/stroke0→1, large area growth.
workshop_sa_folded	1194 /unsupported /726.5	New supported scope, but crossings7→8, contacts19→28, label/node0→3 and label/stroke0→2; four promoted warnings retained.
mixed_dispatch	716.4 /4228 /516.6	Crossings10→7, contacts25→16, no label collisions, larger area.
mixed reversed IDs	512.4 /4228 /462.6	Crossings9→6, contacts26→15; differs from corresponding unpermuted result.
sparse40	1990 /40522 /32	Strong structural improvement; residual label/label1 and label/stroke3 remain.

All successful cases report zero unrelated node penetration and zero unrelated node collision. Necessary lead reports are empty. These emitted facts are not claims of complete glyph or arrowhead clearance.

Structural causal witness

Sparse independently has four ten-node SCCs; each now occupies720×1024 with a5-row/2-column perimeter. Condensation ranks are0,1,2,3 and every intercomponent arc respects increasing rank. Old members sprawled/interleaved across16 ranks. The old y28 top corridor contributed38880 units; the new result has no horizontal shared interval at all. Its entire32-unit sharing is one vertical group at x1510. Thus this result directly supports the diagnosed rank/SCC-locality cause, without any router cost change or lane allocator.

Sparse full vector versus reset: proper crossings94→15, contacts158→19, sharing1990→32, label/node14→0, label/stroke31→3, route length39660→18784; area3804920→4001536 (about5.2% larger). Label/label remains1. Compared with old native, crossings17→15 and sharing40522→32 with substantially less area. This is compelling experimental evidence for coherent SCC placement, not proof of universally separated lanes.

Mixed's six-node SCC occupies706×564 in3×2, with singleton condensation ranks around it. Its previous4006-unit y28 sharing vanishes; remaining sharing is local, largest216 vertical at x709. However its area rises1139880→1667490, and ID-permuted routing differs (sharing462.6 versus516.6, crossings6 versus7). The output therefore cannot be described as invariant to relation-ID permutation. Route length is7349.6 in both, versus10618.6 reset.

Folded retrace: definitions matter

Folded SCC's emitted726.5 shared units are correct under the observer's raw segment-pair definition. Deduplicating edge occupancy per interval yields708.5. Promoted edge a15f7dfd-ac0b-562a-a633-fadc9fb64176 follows:

(747,1052)→(747,1034)→(324,1034)→(324,106)→(330,106)→(312,106).

Its last two horizontal segments retrace x324..330, length6. Other edge overlaps count that span twice in the raw segment-pair sum, explaining the18-unit excess. Independent existing pairwise-segment evaluator also gives726.5. This is not an arithmetic bug; it is both a metric-definition distinction and a real derived backtracking witness relevant to tracing. No silent deduplication should erase it.

Next distinct action and stopping point

Stop this frozen candidate as planned. Retain coherent SCC condensation as the supported structural direction. First diagnose the rejected two-container final-projection mismatch and align planned container/port-capacity geometry with the authoritative projection; do not weaken the equality check or flatten the hierarchy to gain a successful row. This is a concrete integration-contract failure, not a reason to sweep perimeter dimensions.

After that narrow mismatch is resolved, the next quality experiment should target local label/connection corridor placement or ordering on the actual residual witnesses, not global gaps or router penalty changes. Sparse's huge outside trunk is gone; workshop label interference, folded backtracking and bipartite local sharing are different problems. Virtual long-edge ordering is not justified merely by this successful SCC compression; use it only if a residual crossing witness actually involves rank-spanning order. A derived separation pass remains a candidate for fixed-geometry local sharing, with the previously stated stub/label/pin lifecycle constraints.

No production/native acceptance follows from this record. Header/label legibility, overview/navigation cost, selected workflow tracing, production command/history integration and full Project conservation remain separate checks. No additional candidate run or tuning was performed.

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.local\scc-placement-independent-audit-20260925.json: SHA256 10e53afa7e19cf90cd66524451a2bf4723d98abcca8b1b1c4503d466e19c3df2.
.local\scc-placement-independent-audit-v2-20260925.json: SHA256 519baf9fa49238aaa1e2b61e44b1c0e6b9d420b2ed7dcafe7b489d9e01396682.
.local\scc-placement-20260925\run01\receipt.json: SHA256 f84bc9793636a9bb087d465d2d9bb22b39a3bc6ccae595fc60438db4b0c03f18.
.local\elk-reference-20260925\rust-run03\arrange-corpus\stdout.jsonl: SHA256 f924af4038ade0de2e0f44988fa28d2566019d8c4bc2bde70e61fe4813364d40.

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