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Re: Basic Questions about RDF semantics

From: Max Voelkel <max.at.xam.de@gmail.com>
Date: Thu, 21 Apr 2005 14:11:51 +0200
Message-ID: <dd14090d0504210511619e5e0f@mail.gmail.com>
To: carlos.enguix@deri.org, semantic-web@w3.org
Hi Carlos,

I think the validator is correct, but the visualisation isn't.

RDF has triple-set-semantics. It's not illegal to put something twice
in a set. Semantically, it's just one time in the set, no matter how
often you put it in.

http://www.w3.org/TR/rdf-concepts/#section-data-model

"6.2 RDF Graph 

An RDF graph is a set of RDF triples."

Greetings, Max


On 4/20/05, Carlos F. Enguix <carlos.enguix@deri.org> 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:
> 
>  
> Validation Results
> 
> Your RDF document validated successfully.
> ________________________________
> 
> The original RDF/XML document1: <rdf:RDF
> 2:    
> xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
> 3:     xmlns:vcard="http://www.w3.org/2001/vcard-rdf/3.0#"
> >
> 4:   <rdf:Description rdf:about="http://carlosf.enguix.name">
> 5:     <vcard:FN>Carlos F. Enguix</vcard:FN>
> 6:     <vcard:N rdf:nodeID="A0"/>
> 7:   </rdf:Description>
> 8:   <rdf:Description rdf:nodeID="A0">
> 9:     <vcard:Family>Enguix</vcard:Family>
> 10:     <vcard:Given>Carlos F.</vcard:Given>
> 11:     <vcard:Given>Carlos F.</vcard:Given>
> 12:   </rdf:Description>
> 13: </rdf:RDF>
> ________________________________
> 
> Graph of the data model
> 
> 
> 
>  
> 
> Which for me it does not make sense having repeated Given name. Being set
> based the RDF validator would have detected an inconsistency.
> 
> From the meaning perspective it does not make sense.
> 
>  
> 
> Assuming that RDF is in a way "naive" and it is not able to infer that Given
> should be uniquely applied once to the bnode genid:A0. How we could infer
> additional constraints to indicate so or it is outside of the scope of RDF
> and more about a semantic addition to an ontology on top of RDF. 
> 
>  
> 
> Cheers
> 
>  
> 
> Carlos F. Enguix
> 
> Research Fellow Semantic Web Cluster
> 
> Digital Enterprise Research Institute (DERI)
> 
> Science & Engineering Technology Building
> 
> University Road, Galway, Ireland
> 
>  
> 
> Skype ID: cenguix
> 
> Phone(Work): (353) 91 49 5012
> 
> Phone(Home):(353) 91 86 1532
> 
> E-mail: Carlos.F.Enguix@acm.org
> 
> E-mail[ALT] carlos.enguix@deri.org
> 
> WWW: www.carlosf.enguix.name
> 
>
Received on Thursday, 21 April 2005 13:39:11 UTC

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