PM-PTN-0010

A Thing may have several independent state dimensions

Whether a Thing's States form one set or several independent groups is unresolved. An implementation MUST NOT assume either.

Non-normative. The consequence of guessing wrong is large in both directions.

If there is one dimension and a tool offers several, modellers will build orthogonal lifecycles that the engine cannot evaluate and no source sanctions.

If there are several and a tool offers one, modellers will encode the cross-product by hand — PaidUnshipped, PaidShipped, UnpaidUnshipped — which is the classic state explosion, is what statecharts were invented to remove, and makes PO-0003 intractable because the number of co-satisfiable pairs grows multiplicatively.

This is the second question worth a call with Guil rather than an email, after Q-G-0001, and the two are related: partitions are one of the ways state() could be made single-valued.

OPEN MAY · draft · area PTN · since 0.1.1

Source

No source citation — trust token OPEN; see the reasoning above.

Relationships

Blocked by Q-G-0002