The Fintech Builder · D30-F03-A05

Prove the bridge. Keep the investigation open.

Both source bridges can pass while the closing balances differ. Trace independent controls, every booked movement and evidence-derived explanations under one knowledge cutoff.

Proof scenarioCopied register comparisonCopied internal closing comparison

Speed

Internal bridge residual · cents

External bridge residual · cents

Adjusted closing residual · cents

Internal bridge

Every chosen-currency movement

External bridge

Every chosen-currency movement

Selected independent controls

Investigated item evidence

Inspect full source and control histories

These are supplied input histories, including future/unselected versions. Selected output never borrows a future control payload.

Explain the overall outcome

Profile and booking window
Raw opening difference · internal − external
Raw closing difference · internal − external
Internal investigated item signed total
External investigated item signed total
Adjusted internal close
Unresolved investigated item count
Comparison decision

Adjusted internal close = internal close + external item signs − internal item signs. Derive each item amount from its exact current row version; accept no free residual amount.

Any unresolved item prevents a clean pass, even when adjusted residual is zero. A raw opening difference cannot be hidden by current-period items.

Known numeric failure remains fail when the opposite evidence is indeterminate. Malformed or conflicting evidence rejects before arithmetic.

A clean pass establishes arithmetic under trusted heads and controls. It does not authenticate their truth, prove all real transactions were reported, clear suspense or post a journal.