This is where we will think about time. Which is hard. Because it can not be denied...
The decision to use the Library of Congress' Extended Date/Time Format (EDTF) for dates in Who's On First has not^H^H^H^H almost been formalized. Generally, it seems like a good idea.
There are not many working implementations for handling EDTF date strings in code which is not ideal. On the other hand it is the most robust format, to date, for representing ambiguities in dates which is probably the more important criteria in the short-term.
An EDTF date string indicating when a place was "created". The semantics of what created means – a declaration of independence, a recognition of that declaration, it's administrative incorporation and – are left for another dicussion.
An EDTF date string indicating when a place ceased to exist as a political entity or social construct in "popular" culture.
An EDTF date string indicating when a Who's On First record was officially deprecated, for example if the record references a place considered to be invalid.
An EDTF date string indicating when a Who's On First record was superseded into another record. For example if the record was given an
edtf:cessation date and superseded into another record, it would recieve this property.
British North America
wof:name="British North America" edft:inception="1783~" edtf:cessation="1907"
Note: As of this writing we do not actually have a WOF record for British North America. It is included only as an example.
wof:name="Kingdom of Yugoslavia" edtf:inception="1918" edtf:cessation="1941"
wof:name="Socialist Federal Republic of Yugoslavia" edtf:inception="1945-11-29" edtf:cessation="1991-06~/1995-12~"
wof:name="Bosnia and Herzegovina" edtf:inception="1992-03~/1992-04~"
Note: As of this writing we do not actually have a WOF records for Yugoslavia. They are included only as examples.
incorporated as does TGN, for example: Montreal.
Who's On First