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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


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


I parse the following basic example derived from the JENA tutorial:




    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:nodeID="A0">


    <vcard:Given>Carlos F.</vcard:Given>

    <vcard:Given>Carlos F.</vcard:Given>




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. 




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 UTC

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