The plan · The slots · Element
The owner
Who produces it.
The part
What it is
One named person. Where the piece requires an expert contribution, both the owner and the contributor are named, since the second is the risk.
Owners with several slots in the same week is a capacity problem visible at planning time.
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.