Re: OWL-Time extensions for Era

> I recall many threads on this through the years.

I can imagine that yes. My current understanding is that:
- RDF1.0 following XSD1.0 doesn't have a "0000"^^xsd:gYear
- RDF1.1 following XSD1.1 (and ISO8601) does have a "0000"^^xsd:gYear,
defined as 1BCE (so the arithmetic on the lexical value is easier)
see the note on https://www.w3.org/TR/xmlschema11-2/#vp-dt-year . But
I'm happy to be wrong.

So, maybe instead of defining a time:CommonEra resource (which is
ambiguous in terms of "0000"^^time:generalYear), we could define
time:ISOCommonEra so that its use is clearer? That would clarify the
semantics of the lexical value

ex:date1 time:year "0000"^^time:generalYear ;
               time:era time:ISOCommonEra .

> If 'unknown' and 'now' are constructed as temporal positions, not instants, then you could go with
> [...]
> Etc. I think those two will do.

Yes perfect!

Thanks,
-- 
Elie