The calendar · The plan · Element

The horizon

How far ahead the plan is firm.

The part

What it is

Long enough that production and approval have room; short enough that the plan can still answer to what is happening in the market.

The rule for changing a firm slot matters more than the horizon itself. Without one, everything is provisional in practice.

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.