Edits from non-linear constraints. For example, if v1 and v2 are variables and b are real constants, then nonlinear edits are:
1. v1 v2 b.
2. v1 exp(v2).
3. conditional edits.
4. Mahalanobis-distance edits with multivariate normal data.
The importance of nonlinear edits is that they occur often but are not amendable to theory in the determination of a minimal set. Some nonlinear edits, such as ratio edits, can be cast in a linear form.