A matching requirement for an actual field apparatus

If a later construction proposes a field instrument ${\mathcal{J}}_k$, agreement with this pilot would require a specified input embedding or comparison map and equality, or a proved error estimate, for its complete selective maps. Agreement only of the scalar expectations $F_k$, or only of record effects, would not establish residual-instrument agreement.

This is an additional physical realization problem. It is not a missing step in the classical proofs, and those proofs do not solve it automatically.