- From: Benedicto Rodriguez <br205r@ecs.soton.ac.uk>
- Date: Mon, 15 Oct 2007 00:54:16 +0100
- To: <public-owl-dev@w3.org>
Hello everyone, (This post probably belongs to the public-swbp-wg-request@w3.org mailing list, but given that the working group is now closed and the type of questions included, I thought it would be ok to post it here instead). 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
Received on Monday, 15 October 2007 04:17:17 UTC