PM-DRV-0020

An implementation MUST support Derivations of at least the following kinds: admin-configured object property parameters; parameters defining the values in a value-set Property; formulas computing a Property value; data sets scoping by user domain, business unit or region; and external objects required by an object's behaviour.

Non-normative: these five are not variations on one thing. An admin-set scalar, a controlled vocabulary, a formula, a scoped query and a call into a foreign system have nothing in common except that each supplies a value. Bundling them under one construct makes the notation look simpler than it is, and it pushes the complexity into whatever editor a tool eventually offers.

The fifth kind is the one to watch. "External objects required by the object behaviour" is an unbounded hole: a Derivation that calls out to another system can return a different answer on every invocation, which would void determinism entirely. Any implementation has to constrain it — pure, sandboxed, no clock, no network, version-pinned — and say so, rather than inheriting the phrase as written. Recorded as Q-G-0016.