W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > November 2001

RE: DATATYPES: mental dump.

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Fri, 16 Nov 2001 13:18:17 -0600
Message-Id: <p0510107cb81b13965af4@[65.212.118.147]>
To: Patrick.Stickler@nokia.com
Cc: w3c-rdfcore-wg@w3.org
>  > x learnedToCountUpTo http://www.w3.org/2001/XMLSchema#integer:10
>
>No. You wouldn't express it that way. URV's don't themselves
>contain the data type URIs but map to them. I.e.:
>
>You would express it as
>
>   x learnedToCountUpTo <xsd:integer:10>.
>
>and from the definition defined in the schema for
>the 'xsd:' URV schema
>
>   <xsd:integer> lit:mapsTo http://www.w3.org/2001/XMLSchema#integer .
>
>implies
>
>   x learnedToCountUpTo _:1 .
>   _:1 rdf:value "10" .
>   _:1 rdf:type http://www.w3.org/2001/XMLSchema#integer .

Oh. Then I didn't understand this URV proposal either, it seems.

The above doesn't make sense to me.

What sense of 'implies' do you mean? Is the idea that the URV form 
itself would not in fact be syntactically correct RDF? If it IS 
syntactically correct, what process or semantic constraint justifies 
the translation from the plain URV triple containing <xsd:integer:10> 
to the DC-style triplet graph using rdf:type? On the face of it, that 
seem invalid.

>
>And if you had two statements
>
>   x learnedToCountUpTo <xsd:integer:10>.
>   y ageInYears <xsd:integer:10> .
>
>Then your graph would be
>
>    x --learnedToCountUpTo---> <xsd:integer:10>
>                                   ^
>                                   |
>    y --ageInYears------------------
>
>But the interpretation would be
>
>   x learnedToCountUpTo _:1 .
>   _:1 rdf:value "10" .
>   _:1 rdf:type http://www.w3.org/2001/XMLSchema#integer .
>   y ageInYears _:2 .
>   _:2 rdf:value "10" .
>   _:1 rdf:type http://www.w3.org/2001/XMLSchema#integer .

That is not an interpretation. It is a graph. How did you get from 
the first graph to this graph?

>Thus, it is the object slot of the triple that denotes the
>value, not the graph entity filling the slot.
>
>Using URVs allows for far more graph nodes to be tidy and
>thus results in a far more compressed graph, but they
>are only a more concise, compressed "synonym" for the idiom
>
>    x someProperty _:1 .
>    _:1 rdf:value "someLiteral" .
>    _:1 rdf:type   some:type .
>
>Is that clearer?

No, because we don't have any clear meaning for 'synonym'.

Please, please, let us have these proposals made openly. Say what the 
actual RDF graph that expresses the content is going to be. Do not 
invent some kind of syntactic sugar and then appeal to some undefined 
notion of synonym-expansion or rule-application to generate the 
'real' RDF graph.

As far as I can make out from the above, the URV proposal is in fact 
just a syntactic sugaring of the DC proposal, which was taken out of 
the running in todays telecon; so we should treat the U proposal as 
also taken out of the running.

Pat

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Received on Friday, 16 November 2001 14:19:22 EST

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