B32→B40 cross-word target bridge
The exact target ladder can cross from digest word 7 to the first byte of word 6 when the required e62/feedforward identity is included.
Diagnostic work, exact algebra and local capabilities are not treated as end-to-end mining advantage.
What was tested?
The exact target ladder can cross from digest word 7 to the first byte of word 6 when the required e62/feedforward identity is included.
Why the test is meaningful
B32 fixes the first digest word boundary. B40 needs eight more ordered bits from the adjacent word, so state-shift and feedforward identities must be transported rather than assuming the word-7 contract continues unchanged.
B40 = B32 ∧ next8(word6)digest_word6 = e62 + IV6 (mod 2³²)W_total = W_B32 + I(B32)·W_incremental_B40How it was tested
Condition on exact B32 records, reconstruct the necessary word-6 state relation, evaluate the next eight target bits and repeat two independent 20,000-record campaigns with full suffix verification.
What happened
Both replicates had zero B32, e62 and full-suffix errors. Mean incremental B40 work was 45.858 in replicate A and 45.696 in B, on top of the registered 640-unit B32 stage. Rejection-stage distributions followed the expected early-bit concentration.
Exactness and statistical controls
The cross-word identity and final target decision were independently checked. Agreement of two work estimates supports reproducibility but is not converted into an economic claim.
What the result means
The ladder crosses the word boundary exactly. V47 is a capability bridge, not a submotor: it enables later tests without showing total work below a conventional comparison.
Limitations
- The 640-unit stage is a diagnostic accounting convention.
- Only the B32→B40 boundary is covered.
- Producing candidate hashes remains outside the capability.
Evidence trail
Reconstruct word 6 from the anchored state, verify B32 first, evaluate the next byte only for survivors and compare every result with the full digest target.
Canonical variants
SUBENGINE-V47ASUBENGINE-V47BSUBENGINE-V47CSource: internally audited canonical reports. Local filesystem structure, private headers and operational identifiers are excluded from publication.