The 2026 S4+SPNSA paper's own ablation traces most of its illicit-enrichment gain to feed selection, not to SPNSA's shortest-path aggregation step

amlanti-money-launderingtransaction-networksgraph-algorithmsspnsaarxivablation

To separate the contribution of feed choice from what SPNSA's shortest-path aggregation adds on top, a 2026 preprint on AML subgraph extraction compares its full S4-feed-plus-SPNSA output against the subgraph simply induced by the S4 feed nodes alone, with no path-finding step at all. On three of the four datasets tested, the induced-feed-only subgraph exceeded the illicit ratio of the full SPNSA output (Table 4: Elliptic 0.355 vs 0.338, HI-Small 0.290 vs 0.222, HI-Medium 0.435 vs 0.262); on LI-Small it was marginally lower (0.055 vs 0.056) — the authors' summary "equal to or higher" rounds that one case. The authors read this as showing that the enrichment their headline results report comes from which nodes the motif-based strategy (S4) selects as the feed, not from SPNSA's own path-aggregation mechanism — which mainly contributes additional path-based "connector" nodes, and can occasionally dilute concentration rather than improve it.

This narrows what the paper's title suggests is novel: SPNSA itself is not new (see claim-spnsa-originated-2015-on-enron-email-corpus-not-financial-transactions), and this ablation shows the paper's actual contribution — a new feed-selection heuristic — accounts for most of the measured gain reported in claim-spnsa-motif-feed-selection-outperforms-baselines-but-not-universally, independently of whether SPNSA's downstream aggregation step is used at all.

This is a specific technical-mechanism claim about where a result's effect actually originates, which the sourcing floor holds to Tier 1–2; it is cleared directly, since the claim is the authors' own stated interpretation of their own ablation table (Table 4, Appendix) in the same Tier 1 preprint.