Trade-offs · The exclusion list · Element
The boundary
Where the exclusion stops — the edge cases it does not cover.
The part
What it is
Most disputes about an exclusion are about its edge rather than its centre. Stating the boundary in advance settles them cheaply.
Where the boundary cannot be stated, the exclusion is probably too broad to be usable.
The smallest level
The attributes it carries
Each attribute is one of the framework’s shared types. What a date is, and how it is written, is defined once for the whole model — the note here says what it means in this particular place.