Exact operator cancellation with unchanged scalar data

of agreement. Perfect-copy screening is a termwise sufficient certificate. Residual distinguishability changes the norms of surviving terms. Operator cancellation concerns their weighted Hermitian sum. Question-specific agreement concerns the final linear functional $Y\mapsto \mathrm{tr}(MY)$, and includes commuting questions as well as cancellation between nonzero scalar contributions. Higher-order Möbius behavior concerns the dependence on record sets. These are useful distinctions, not an exclusive five-way partition: attenuation need not yield exact agreement, and several mechanisms may coexist.