B.5.RR:4.3 - Derive what follows after the change

Work from available premises through the affected transitions. Reuse a contribution whose conditions and required result still fit. Where they do not, derive the replacement, select an adequate alternative or identify the unresolved step.

Withdrawing a premise removes that premise as a basis for asserting the conclusion. Another sufficient argument may still support it. To assert the opposite conclusion, obtain a reason for that assertion. The conditional argument can remain available for situations in which its premises hold.

Follow the change through each needed use of a shared prerequisite. Keep the premises of an alternative argument together: pieces from two incompatible situations do not form a supported argument for either situation. If conclusions refer back to one another, recover the grounding of that reasoning, such as an initial case and induction step. Mutual repetition alone cannot replace the starting support.

A changed requested result can require working backward as well. Identify what the new conclusion would need, reuse the earlier contributions that supply it, and produce the remaining contribution. Release a former fixed value when the question now asks you to determine it.

Compare the work of recovering and repairing the affected reasoning with the work of obtaining a fresh sufficient answer. A short new calculation can be cheaper and clearer. A maintained dependency account is useful when repeated revisions repay its cost; it is optional for an ordinary one-off question.