Check each transformation, not just the endpoints.
Workflow
- Rewrite the derivation step by step.
- For each step, justify the rule used.
- Flag silent assumptions such as differentiability, invertibility, exchange of limits, or independence.
- Verify dimensions, domains, signs, and constants.
- Mark the first invalid or unproven step exactly.
- If the derivation is valid only under added conditions, state the weakest conditions you found.
Rules
- Do not skip steps that are essential to the argument, even if they seem obvious.
- If a derivation is only heuristic, explicitly label it as heuristic.
- Distinguish algebra mistakes from missing assumptions.
- Do not repair the derivation silently; name the repair.
Output
Return:
- target derivation;
- checked step list;
- first invalid or unsupported step;
- required assumptions;
- corrected version if small enough;
- verdict: valid / valid with conditions / heuristic / invalid.