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Re: ACTION: task force unasserted triples

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Wed, 24 Apr 2002 12:36:37 -0500
Message-Id: <p05101531b8ec9c799d40@[65.217.30.94]>
To: jos.deroo.jd@belgium.agfa.com
Cc: www-webont-wg@w3.org
>[...]
>
>>>Some further thoughts...
>>>Suppose we want to say
>>>    :John a [ owl:intersectionOf ( :Student :Employee ) ] .
>>>
>>>which is in triples***
>>>
>>>    :John a _:a0 .
>>>    _:a0 owl:intersectionOf _:a1 .
>>>    _:a1 owl:first :Student .
>>>    _:a1 owl:rest _:a2 .
>>>    _:a2 owl:first :Employee .
>>>    _:a2 owl:rest owl:nil .
>>>
>>>Now suppose I'm so clumsy to create http://www.agfa.com/w3c/n3/ta.n3
>>>
>>>    :John rdf:type _:a0 .
>>>    _:a0 owl:intersectionOf <http://www.agfa.com/w3c/n3/ti.n3> .
>>>
>>>and http://www.agfa.com/w3c/n3/ti.n3
>>>
>>>    _:a1 owl:first :Student .
>>>    _:a1 owl:rest _:a2 .
>>>    _:a2 owl:first :Employee .
>>>    _:a2 owl:rest owl:nil .
>>>
>>>This is not to say that we should do it in that way,
>>>just to say that it could be thought in that way.
>>>I'm now asserting ta.n3 but what happens while
>>>asserting the owl:intersectionOf statement?
>>>Because we have to have a list of classes it's
>>>quite obvious that we have to dereference our uri
>>>to get that (functional) term in our engines.
>>>Does that mean that we also have to *assert* the
>>>statements in ti.n3? Not at all I think.
>>>We are not ``talking'' about _:a1, but ``using'' it.
>>
>>Right, I like this idea. It is simple, straightforward, practical,
>>and it requires no change to RDF (though it does come close to
>>violating Dan C's notion of what it means to publish an RDF graph).
>>OWL needs to add some extra meaning to RDF, but  that is what one
>>would expect, and the extra meaning involved is very 'webbish' and
>>natural-seeming, involving using URIs as, well, URIs.
>>
>>But I had the distinct impression that this option was ruled out at
>>the Amsterdam F2F on the grounds that any solution that involved
>>"lots of little files" wasn't acceptable. That was late on the second
>>day, and things were a little chaotic, but since then I have been
>>working on the assumption that we have to find some other way to do
>>it. If that assumption is wrong, maybe someone else who was at the
>>meeting can correct my memory.
>
>That's true, is also my recollection
>?? BUt before we go on, do we have a use/mention bug
>in above triples*** ?? (I think we do, because
>we are not ``talking'' about _:a1, but ``using'' it)

Yes. Well, maybe. Its kind of hard to say quite what things like this 
really do mean, since the only case example we have is DAML, and 
giving a convincing layering of the DAML MT onto the RDF MT still has 
not yet been done. We could just *define* the DAML meaning to be one 
that ignores this much "use" in the RDF, which I think amounts to 
having dark triples under a different name.

>If so, then I think that knowing that _:a1 has to be
>``used'' (by value) could also work.

What would the actual criterion be for recognizing such 'use', 
though? Wouldnt it amount to the same as darkening the first/rest/nil 
vocabulary?

Pat
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Received on Wednesday, 24 April 2002 13:36:39 GMT

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