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Re: Basic Questions about RDF semantics

From: Jeen Broekstra <jeen@aduna.biz>
Date: Thu, 21 Apr 2005 14:18:11 +0200
Message-ID: <42679A03.4010802@aduna.biz>
To: carlos.enguix@deri.org
Cc: semantic-web@w3.org

Carlos F. Enguix wrote:
> Hi all, I hope I find somebody to help me understand more about RDF 
> semantics…
> I am reading the RDF Semantics documents and I do have clear some things.
> Is it an RDF graph set theoretic based in other words an RDF graph per 
> ser contains a set of triples and not a bag or multiset?
> I run the validator against some simple examples and come up it is not 
> set-based:
> I parse the following basic example derived from the JENA tutorial:
> <rdf:RDF
>     xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>     xmlns:vcard="http://www.w3.org/2001/vcard-rdf/3..0#" >
>   <rdf:Description rdf:about="http://carlosf.enguix.name">
>     <vcard:FN>Carlos F. Enguix</vcard:FN>
>     <vcard:N rdf:nodeID="A0"/>
>   </rdf:Description>
>   <rdf:Description rdf:nodeID="A0">
>     <vcard:Family>Enguix</vcard:Family>
>     <vcard:Given>Carlos F.</vcard:Given>
>     <vcard:Given>Carlos F.</vcard:Given>
>   </rdf:Description>
> </rdf:RDF>
> And the validator gives me:

[snip result showing to arcs with vcard:Given property]

> Which for me it does not make sense having repeated Given name. Being 
> set based the RDF validator would have detected an inconsistency.

This is a small bug in the validator I think, it should have drawn 
only one arc in the picture (apparently it does not unify identical 
literals). However, it is not inconsistent or otherwise an error to 
have two identical statements in your RDF data, it is merely redundant.

Jeen Broekstra          Aduna BV
Knowledge Engineer      Julianaplein 14b, 3817 CS Amersfoort
http://aduna.biz        The Netherlands
tel. +31 33 46599877
Received on Thursday, 21 April 2005 12:16:14 UTC

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