an exercise is individuated by what it does

agent-decided, reversible. A challenged replay may re-admit an event and have it act differently. Whether that counts as the same exercise surviving is a choice with consequences: under event identity the issuance-stability axiom needs the record's schemas to be pre-state-blind, and under effect identity the origin-necessity axiom needs it instead. The condition does not go away, so the choice is made on semantics — an act that does something else is not the same act — and the realization defaults to effect identity.

The prosecution is the reason this is recorded rather than assumed: the round's first reading was that a finer identity would remove the hypothesis, and a record whose effect changes in one component and not another shows it does not.

Rejected alternative: identifying an exercise with the event id, which is what the first pass used and what makes C28 a defect rather than a repair.

Record: projects/normativity/legitimacy/rounds/2026-08-25-legitimate-evolution/LEGITIMATE_EVOLUTION.md §8.1.