W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > February 2002

RE: Oh my GOD, another datatype document.

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Wed, 6 Feb 2002 10:04:24 -0600
Message-Id: <p05101436b88701e06e12@[65.212.118.208]>
To: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>
Cc: w3c-rdfcore-wg@w3.org
>Pat
>
>a simple Yes/No question.
>
>Does the doublet stuff work for the following case:
>
>
><Jenny> <age> _:a .
>_:a <value> "10" .
><age> <range> <xsd:int> .

Yes. Given the semantic conditions on <range>, and knowing that 
<xsd:int> is a datatype, this entails the 'local' version
<Jenny> <age> _:a .
_:a <value> "10" .
_:a <dtype> <xsd:int> .

Technically, the first graph with

<xsd:int> <type> <Datatype> .

added to it entails that,  ie you have to 'say' that xsd:int is being 
used here as a datatype, not just being talked about.  That is to 
allow one to say things like

<xsd:int> 
<http://www.lab.whatever.edu/users/phayes/opinions#SincerelyHeldView> 
"sucks" .

without automatically being committed to xsd datatyping.

>My question is about the lack of an explicit triple giving the dType, this
>was one of my problem cases in the TDL model theory.

The whole point of the 'ranging' semantic condition is to allow 
<range> info to entail <dtype> info, so that if the 'local' idiom 
works then the 'global' one will as well (though you have to do some 
extra inference, of course). It works for all the cases that use 
bnodes, but it doesn't work very well for the inline-literal case.

Thats also why one needs to use a separate namespace (or some 
equivalent trick) to stop having too many possible leaks from 
rdfs:range to rdf:type. If we only used local typing there wouldnt be 
any real need for that.

Pat


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Received on Wednesday, 6 February 2002 11:03:51 EST

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