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Re: ACTION 2001-08-24#9 : issues with containers

From: pat hayes <phayes@ai.uwf.edu>
Date: Tue, 4 Sep 2001 13:00:12 -0700
Message-Id: <v04210108b7bae27435d3@[130.107.66.237]>
To: Jan Grant <Jan.Grant@bristol.ac.uk>
Cc: w3c-rdfcore-wg@w3.org
>On Mon, 3 Sep 2001, Dan Connolly wrote:
>
> > Again, suppose the graph had a Bag rather than an Alt:
> >
> >       <doc1> <dc:creator> _:a .
> >       _:a <rdf:type> <rdf:Bag> .
> >       _:a <rdf:_1> <jan> .
> >       _:a <rdf:_2> <dan> .
>
>I don't consider the two to be interchangable. Why? Compare
>
>	http://ioctl.org/rdf/ms/rdfms#108
>"The students in course 6.001 are Amy, Tim, John, Mary, and Sue."
>It seems here that the collection itself is truly considered the value
>of a property, whereas...
>
>	http://ioctl.org/rdf/ms/rdfms#111  (and #112)
>"Here, any one of the items listed in the container value for
>DistributionSite is an acceptable value without regard to the other
>items."
>
>In other words, the Alt-collection itself isn't really being considered
>the value of the property; the members of the Alt are being considered
>so instead.*
>
> > We don't license the inference that
> > 	<doc1> <dc:creator> <jan>.
> > in that case, do we? No. Then why should rdf:Alt have any magic
> > associated with it?
>
>Because clearly they don't behave in the same way, so the analogy isn't
>sound.
>
>I'd rather see Alt go away - the examples in M+S are vague and subject
>to this kind of confusion.
>
>jan
>
>* although there are two kinds of alternative notion: the one in this
>example is "this is true for ever member of the Alt, just pick one" (so
>why isn't it just a bag?)

Right. Although there is one possible answer in the M&S (an aspect 
that I ignored), which is that an Alt is required to have at aleast 
one element, which is the first, and is considered the 'default' 
value. So an Alt might be a bag with a default first member, maybe. 
(However, the need for this default suggests that as you say above, 
the members are the intended values, not the alt container itself.)

>as opposed to "this is true for at least one
>member of the alt" - which is where you need some MT support (I think).

Yes, I think so also.

Pat

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Received on Tuesday, 4 September 2001 15:58:55 EDT

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