6.13.2.24 ObservedPeriod

6.13.2.24.1 Purpose

A time interval whose start and end keep their precision, with an explicit open or unknown end.

6.13.2.24.2 Fields

Field	Type	Cardinality	Description
start	EventTime	1..1
end	EventTime	0..1
end_state	enum	1..1	Values: known, open, unknown.

6.13.2.24.3 Relationships

Uses types

EventTime

Used by

• Batch.cycle
• CanonicalPeriod.period
• ObservationTime.interval

6.13.2.24.4 Rules & constraints

• Known requires non-unknown end; open/unknown have no end. Start may explicitly be unknown.
• [start,end) when known; preserve calendar precision and require end ≥ start wherever ordering is decidable.
• Open is explicitly ongoing; unknown is not proven ongoing. A date precision does not justify an invented hour.