34. Applying the calculus to a domain: the model template🔗

The preceding chapters say what the calculus is and what it proves. This one is guidance for the domain expert who builds on them: what a domain model owes to its reader, and how a document can report, on every build, which of those obligations it has discharged.

The obligation is not obvious, and getting it wrong is cheap. A model that declares its kinds, proves its algebra and ships green nodes can still leave a reader unable to answer the questions that decide whether the model may be used — what it is a model of, which of its quantities the dimension layer cannot separate, at which carrier each theorem holds, and which of its numbers were proved rather than measured. None of those is a matter of taste: each has an answer, and a document either contains it or it does not. The template below is that list of questions.

1. 34.1. What a template is, and what it is not
2. 34.2. The template
3. 34.3. The premise — what the model is a model of
4. 34.4. The kind vocabulary — and the audits that close it
5. 34.5. The model as modules
6. 34.6. Carriers, adequacy and uncertainty
7. 34.7. Well-posedness and honest failure
8. 34.8. Assurance — and what a green status does not mean
9. 34.9. What the machine can hold, and what it cannot
10. 34.10. How a document declares conformance