Reconstruct the dependency graph
Start by listing the conventions, definitions, and intermediate identities that each nontrivial equation depends on. A derivation is difficult to audit when assumptions are mixed with consequences.
Mark every step as assumed, derived, numerically checked, or unresolved. The labels are more valuable than a premature green check because they preserve where human judgment is still required.
Attack the result from the edges
Check dimensions, signs, symmetries, and limiting cases before reproducing every intermediate line. These tests are cheap and often localize the first inconsistency quickly.
When two formulations are claimed to agree, require an explicit dictionary between variables and regulators. Numerical agreement at one parameter point is evidence, not an equivalence proof.
Suggested citation
Deng, Feiyu. “How to audit a long analytical derivation.” feiyudeng.com, 2026-07-13.