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Basic Questions about RDF semantics

From: Carlos F. Enguix <carlos.enguix@deri.org>
Date: Wed, 20 Apr 2005 20:39:23 +0100
To: semantic-web@w3.org
Message-id: <01LNBW9JWZO0009JTA@beacon.nuigalway.ie>
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 document

1: <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


graph representation of RDF data

 

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]  <mailto:carlos.enguix@deri.org> carlos.enguix@deri.org

WWW: www.carlosf.enguix.name

 





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Received on Thursday, 21 April 2005 11:57:40 GMT

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