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time ontology should allow "conference1 after conference2"

From: Dan Connolly <connolly@w3.org>
Date: Tue, 21 Feb 2006 18:05:02 -0600
To: public-swbp-wg@w3.org
Message-Id: <1140566702.26363.606.camel@dirk.w3.org>

I just found
 http://www.isi.edu/~pan/SWBP/time-ontology-note/time-ontology-note.html
via WG minutes and such.

:TemporalEntity
      a       owl:Class ;
      rdfs:subClassOf :TemporalThing ;
      owl:equivalentClass
              [ a       owl:Class ;
                owl:unionOf (:Instant :Interval)
              ] .

and the domain/range of intBefore is constrained to TemporalEntity.
So I can't just say
  :conference1 swbp-time:intBefore :conference2.
without implying that :conference1 is an :Instant or :Interval.
I have to have some property that relates a conference to
a time interval, and then use :intBefore on that.

I can't see any reason for the indirection.

The cyc ontology seems to express all the relevant stuff
without this constraint. The cyc after relationship
applies to not only instants and intervals, but also
conferences, meetings, people, etc.

http://www.cyc.com/cycdoc/vocab/time-vocab.html#after

The TemporalThing class is also not constrained to be
contiguous/convex; if a meeting goes from 9am to 5pm
Monday and Tuesday, it's still OK to call it a cyc:TemporalThing,
even though it's got a hole.
http://www.cyc.com/cycdoc/vocab/time-vocab.html#TemporalThing

I'm not sure whether this in-progress draft is constrained
to have convex temporal objects, but I was just reviewing SUMO
the other day, and it _is_ constrained to convex intervals,
and I can't see why.


p.s. in turtle, rather than
  owl:maxCardinality "1"^^xsd:nonNegativeInteger 
you can just write
  owl:maxCardinality 1.


-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Wednesday, 22 February 2006 00:05:06 UTC

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