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Re: addressing requirements around daml:collection (rdfms-seq-representation)

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Tue, 23 Apr 2002 14:29:56 -0500
Message-Id: <p0510151cb8eb6615d844@[65.217.30.94]>
To: Dan Connolly <connolly@w3.org>
Cc: w3c-rdfcore-wg@w3.org
>On Mon, 2002-04-22 at 17:35, Pat Hayes wrote:
>>  >[...]
>>  >
>>  >>  RDF/xml has special syntax for containers, but experience
>>  >>  trying to exploit it to come to intuitive conclusions
>>  >>  has exposed problems. Take the class above... say
>>  >>  Continent is the subject of that oneOf property.
>>  >>  If we know
>>  >>
>>  >>     ex:Bob daml:differentIndividualFrom ex:Eurasia.
>>  >>     ex:Bob daml:differentIndividualFrom ex:Africa.
>>  >>     ex:Bob daml:differentIndividualFrom ex:North_America.
>>  >>     ex:Bob daml:differentIndividualFrom ex:South_America.
>>  >>     ex:Bob daml:differentIndividualFrom ex:Australia.
>>  >>     ex:Bob daml:differentIndividualFrom ex:Antarctica.
>>  >>
>>  >>     ex:NotContinent daml:complementOf ex:Continent.
>>  >>
>>  >>  then we should be able to conclude
>>  >>
>>  >>     ex:Bob rdf:type ex:NotContinent.
>>  >>
>>  >>  Now this works perfectly well* when the oneOf claim
>>  >>  is spelled out long-hand using first/rest/nil.
>>
>>  [To Dan:]
>>  Well, that isn't clear.
>
>Sigh... I should have known better than to make that claim
>without working out the details...
>
>>  After all, it is RDF-legal to add some other
>>  rest/first/rest chains to the same bnodes,
>
>Well, first and rest are UniqueProperties.

There isn't any such notion in RDF. I said it was RDF-legal. I know 
its not DAML-legal.

>i.e. if
>
>	:x ont:first :y.
>and
>	:x ont:first :z.
>then
>	:y ont:equivalentTo :z.
>
>So if you add other first/rest chains, you claim
>the relevant gizmos denote the same thing. If that's
>not the case, you've contradicted yourself.

Not in RDF you havn't.

>
>>  so the daml:list is just
>>  as dependent on a closed-world assumption
>
>I don't see any closed world reasoning in saying
>that first/rest are functional/unique properties.
>
>>  as the RDF container syntax
>>  would be in this context. I bet that your (and Jos) code would break,
>>  or act unpredictably, if given a branching daml:list.
>
>Well, 'unpredictably' is probably a reasonable way to
>characterize the behaviour of a prover when given
>inconsistent input.

Its not inconsistent in RDF. That is the point.

Pat
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Received on Tuesday, 23 April 2002 15:30:10 EDT

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