Functional Decomposition

A decomposition process executed in the functional domain. The completeness criterion is to show that the sub-functions (“child functions”) effect the state change (or maintenance) that spans the function being decomposed (“parent function”). Re-parameterization of the system’s state vector is an acceptable means of demonstrating completeness, provided that the re-parameterization is at-least-locally¹ deterministic² in both directions.

A functional decomposition was one of the two methods of grouping “lower tier requirements” in a Prime Item B Specification, the other being a Physical Decomposition.

Footnotes

1. i.e., the use the concept of topological manifolds is acceptable, provided that the scopes of each are not mutually contradicting.[↩]
2. i.e., guessing is not supposed to be allowed in either direction. In practice, of course, GOOD guessing is not only tolerated, but often encouraged.[↩]