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Fwd: Representing anonymous individual in SemWeb Best Practice documents

From: Alan Rector <rector@cs.man.ac.uk>
Date: Sat, 27 Oct 2007 11:25:47 +0100
Message-Id: <0309BB2A-6EE7-4742-871B-CAEAFFF27D3C@cs.man.ac.uk>
Cc: best-practice list <public-swbp-wg@w3.org>
To: Bijan Parsia <bparsia@cs.man.ac.uk>, Matthew Horridge <mhorridge@cs.man.ac.uk>
All

For the future, Is there a serious requirement for OWL to be  
expressed in N3? The original choice was very much a compromise, and  
it looks like we
did not always get it right.

Regards

Alan


Begin forwarded message:

> Resent-From: public-swbp-wg@w3.org
> From: "Benedicto Rodriguez" <br205r@ecs.soton.ac.uk>
> Date: 17 October 2007 01:23:10 BDT
> To: <public-swbp-wg@w3.org>
> Subject: FW: Representing anonymous individual in SemWeb Best  
> Practice documents
>
>
>
> -----Original Message-----
> From: Benedicto Rodriguez
> Sent: 15 October 2007 00:54
> To: 'public-owl-dev@w3.org'
> Subject: Representing anonymous individual in SemWeb Best Practice
> documents
>
>
> Hello everyone,
>
> [...]
>
> Two of the documents in the SWBPD WG ([1], [2]) talk about  
> representing
> anonymous individuals as the value of a property using an existential
> restriction.
>
> [1] Representing Classes As Property Values on the Semantic Web. (See:
> Approach 4). http://www.w3.org/TR/swbp-classes-as-values/
>
> [2] Representing Specified Values in OWL: "value partitions" and  
> "value
> sets". (See: Pattern 2, variant 2).
> http://www.w3.org/TR/swbp-specified-values/
>
> In both cases only the N3 syntax for this variant is provided, not the
> corresponding OWL implementation.
> According to both documents the resulting OWL implementation is within
> OWL-DL expressivity.
>
> *** My goal is simply to write this OWL implementation within OWL- 
> DL but
> I run into some problems doing so.
>
> A) 	I noticed that the N3 syntax provided in [1] and [2] for this
> variant doesn't parse in the only N3 validator online I found
> (http://rdfabout.com/demo/validator/ listed in the SemanticWebTools  
> page
> of the ESW Wiki).
>
> Now, I'm not sure if this is because the N3 syntax is actually NOT
> correct or because of an issue with the parser. (?)
>
> In [2] for example. To parse this variant I used the file
> http://www.w3.org/TR/swbp-specified-values/value-partitions- 
> variant-1.n3
> (provided in [2]) replacing the definition of :John in the file for  
> the
> definition shown below (also provided in [2]) and after a couple of
> tweaks to bypass an empty relative URI issue:
>
> ### Define John as an individual of type person and of type
> has_health_status someValuesFrom Good_health_status
> :John
>     a      :Person ;
>     [    a      owl:Restriction;
>          owl:onProperty :has_health_status ;
>          owl:someValuesFrom :Good_health_value
>     ].
>
> B) 	The following modification to the previous N3 snippet solved the
> parsing problem, but I'm not sure if this is what the original N3
> expression shown in A) intended to represent (?):
>
> :John
>     a      :Person ;
>     :has_health_value
>         [    a      owl:Restriction;
>              owl:onProperty :has_health_status ;
>              owl:someValuesFrom :Good_health_value
>         ].
>
> Now, I have tried 2 options when converting the N3 snippet shown in A)
> into OWL.
> (Again, the original claim in [1] and [2] is the representation of an
> anonymous individuals as the value of a property using an existential
> restriction).
>
> C) 	Option 1: This OWL implementation would place the model is in
> OWL Full because the value of the property "has_health_status" is an
> anonymous class defined by a restriction rather than an anonymous
> individual.
> This deviates from the intention in [1] and [2].
>
> <Person rdf:about="#John">
>    <has_health_status>
>       <owl:Restriction>
>  	   <owl:someValuesFrom>
>             <owl:Class rdf:about="#Good_health_value"/>
>          </owl:someValuesFrom>
>          <owl:onProperty>
>             <owl:FunctionalProperty rdf:about="#has_health_status"/>
>          </owl:onProperty>
>       </owl:Restriction>
>    </has_health_status>
> </Person>
>
> D) 	Option 2: This OWL implementation leaves the model in OWL-DL
> because the value of the property "has_health_status" is an anonymous
> individual from the class "Good_health_value".
> However it doesn't seem to correspond to the original N3 expression
> given that it lacks the "someValuesFrom" restriction.
>
>   <Person rdf:about="#John">
> 	  <has_health_status>
> 		<Good_health_value/>		
> 	  </has_health_status>
>   </Person>
>
> E) 	The same issues and same possible solutions apply to the
> representation of :LionsLifeInThePrideBook in Approach 4 in document
> [1]:
>
> :LionsLifeInThePrideBook
>       a       :Book;
>       [ a       owl:Restriction ;
>                 owl:onProperty dc:subject ;
>                 owl:someValuesFrom :Lion      ];
>       rdfs:seeAlso <http://isbn.nu/0736809643> ;
>       :bookTitle "Lions: Life in the Pride" .
>
> In conlusion, any suggestions of what the OWL-DL implementation of the
> N3 snippet in A) should be?
> Is the OWL in D) a sensible solution?
>
> Additionally, any comments regarding what may be causing the parsing
> issue of the N3 shown in A)?
> Do you think the modification shown in B) (that parses OK), is what  
> [2]
> intended to represent?
>
> Any other comments/feedback would be very welcome and appreciated.
>
> Regards,
> Bene Rodriguez
>
> Postgraduate Student | Intelligence, Agents and Multimedia Group |
> School of Electronics and Computer Science | University of  
> Southampton |
> Southampton SO17 1BJ | United Kingdom | Phone: +44 23 8059 3122 |  
> Email:
> bene@soton.ac.uk
>

-----------------------
Alan Rector
Professor of Medical Informatics
School of Computer Science
University of Manchester
Manchester M13 9PL, UK
TEL +44 (0) 161 275 6149/6188
FAX +44 (0) 161 275 6204
www.cs.man.ac.uk/mig
www.clinical-esciences.org
www.co-ode.org
Received on Saturday, 27 October 2007 20:31:21 UTC

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