Account A starts at 100 units before this batch. Each accepted event adds its signed delta; these are not full balance snapshots. Durable event identity is (source, event_id), and the first valid accepted payload is immutable. An exact retry has no new effect. A later different payload with the same identity is quarantined and does not replace the accepted event. Corrections must be new authorized events with their own identity and a reference to the original event. All rows below target A and the correction is authorized. Process them in the stated delivery order.
The problem
Account A starts at 100 units before this batch. Each accepted event adds its signed delta; these are not full balance snapshots. Durable event identity is (source, event_id), and the first valid accepted payload is immutable. An exact retry has no new effect. A later different payload with the same identity is quarantined and does not replace the accepted event. Corrections must be new authorized events with their own identity and a reference to the original event. All rows below target A and the correction is authorized. Process them in the stated delivery order.
| Delivery | Source | Event ID | Delta | Correction reference |
|---|---|---|---|---|
| 1 | payments | e1 | +40 | None |
| 2 | payments | e2 | -15 | None |
| 3 | payments | e1 | +40 | None |
| 4 | payments | e2 | -12 | None |
| 5 | adjustments | e1 | +5 | None |
| 6 | payments | e3 | +3 | payments/e2 |
| 7 | payments | e3 | +3 | payments/e2 |
Give the final balance, accepted identities, no-effect deliveries and conflict record. Explain why maximum-version or last-arrival selection cannot compute this ledger.
Reference answer
Then expect these follow-ups
Delivery 4 arrives before delivery 2 in a replay. Which durable accepted-state record or source authority must preserve the original acceptance decision, rather than applying the first-arrival policy again from an empty store?
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