L91 · Backtest parity is a function, not code — NEO
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parity sealed

L91 Backtest parity is a function, not code

codified 2026-04-26 · V129-S4 · 7 references

Parity means bit-identical output on shared input. Shared module is not a guarantee. Test the function, not the implementation.

Authority

This lesson is recorded as sealed doctrine on the parity surface, sealed at stage V129-S4. Mutations of the rules it governs require operator-directive trace plus verifier sign-off (Rule 13.1.c).

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L90 · Precedent re-read before re-implementation
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