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Re: time ontology should allow "conference1 after conference2"

From: Dan Brickley <danbri@danbri.org>
Date: Tue, 21 Feb 2006 19:24:31 -0500
To: Dan Connolly <connolly@w3.org>
Cc: public-swbp-wg@w3.org
Message-ID: <20060222002431.GC22668@postdiluvian.org>

* Dan Connolly <connolly@w3.org> [2006-02-21 18:05-0600]
> 
> 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

I can imagine that 'afterness' might mean slightly different things
when relating different types of entity. So doing away with the
indirection is tempting. But sometimes a thing is a member of multiple
independent classes; eg. be both an xyz:Person, an abc:Employee and 
cde:RFIDTaggedEntity. Since we can't rely on typing information always
being present, this makes me wary of overloading 'after', since 
multiple class membership could bring different interpretations of 
afterness to bear.

That said, from the definition at 
http://www.cyc.com/cycdoc/vocab/time-vocab.html#after I don't see 
how it applies to people, meetings and random other types, 
"A #$PrimitiveTemporalPredicate  that relates two points in time.
(#$after LATER EARLIER) means #$TimePoint  LATER is after (occurs later
in time than) #$TimePoint EARLIER."

Does some other bit of Cyc model people, conferences etc as 'time
points'? Or am I missing something obvious?

Dan
Received on Wednesday, 22 February 2006 00:24:39 UTC

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