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Re: to pull or not to pull [was: Re: Entailment and bags (was:Re: Agenda items for the f2f)]

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Thu, 14 Feb 2002 17:52:49 -0500
Message-Id: <p05101428b891efa552cc@[192.168.0.6]>
To: Brian McBride <bwm@hplb.hpl.hp.com>
Cc: w3c-rdfcore-wg@w3.org
>We are talking about rdf:Alt here:
>
>At 16:23 13/02/2002 -0500, Pat Hayes wrote:
>>>At 09:38 11/02/2002 -0600, Pat Hayes wrote:
>>>[...]
>>>>Oh well, sure, if we ignore the semantics then we can do 
>>>>anything. The problem with Alt is that if you follow the, er, 
>>>>hint, then your conclusions actually *contradict* valid RDF 
>>>>conclusions, ie in this sense Alt is nonmonotonic.
>>>
>>>Are you suggesting that we pull it entirely?
>>
>>Yes.
>>
>>>That will break anything that's used it.
>>
>>Right. Well, it will make it nonconformant, at any rate.
>>
>>>Saying its meaningless, is wimpier, but safer.
>>
>>Well, its not clear that it is safer in the long run. After all, 
>>the actual CODE will still work, right? But we will be clear that 
>>it isn't conformant. Lack of that clarity is itself dangerous, I 
>>would suggest.
>
>It seems clear to me.  Experiemental explanatory text:
>
>[[
>
>A resource of type rdf:Alt is an ordered collection.  A collection 
>may be given the type rdf:Alt, as opposed to rdf:Bag or rdf:Seq, as 
>a hint to the reader that typical processing by an application will 
>be to select one member of the collection for processing.  For 
>example, a schema designer might use rdf:Alt to represent the 
>collection of mirror sites from which a file may be downloaded.  In 
>all respects, other than this hint, a resource of type rdf:Alt is 
>just like an rdf:Seq.
>
>]]

I'm happy with that.  Final sentence might be rephrased along the lines:

RDF however supports no formal entailments that reflect such hints, 
and considers rdf:Alt to be simply a class of ordered containers.

Pat
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Received on Thursday, 14 February 2002 17:52:49 EST

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