NOT.5:4.3 - Perform the receiving operation and recover its answer

Translate a small source expression, perform the intended operation in the target and interpret the result as an answer to the original question. Show the return explicitly. If the target gives a list of numbered nodes, say which source nodes those numbers refer to. If it supplies only a bound or a set of possible answers, retain that limitation on return.

Compare this result with what follows from the source under its declared interpretation. A mismatch locates a failed translation rule, a missing premise or a target operation that answers a different question. Repair the affected correspondence before relying on that answer.

A target-side answer can be spurious for the source if the target admits additional possibilities. Retain the source restriction or construct the needed reflection argument. For example, allowing arbitrary real values does not preserve a source question that admits only whole counts.

One successful expression establishes that case. A reusable translation needs an argument for its admitted family, such as a rule-by-rule construction over expressions. A separating example can refute a proposed general claim. Additional checking is warranted when its result can change the use or repair of the translation.