W3C home > Mailing lists > Public > www-webont-wg@w3.org > February 2003

Re: OWL Syntax

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Tue, 25 Feb 2003 13:58:40 -0500 (EST)
Message-Id: <20030225.135840.28509917.pfps@research.bell-labs.com>
To: jjc@hpl.hp.com
Cc: www-webont-wg@w3.org

From: Jeremy Carroll <jjc@hpl.hp.com>
Subject: Re: OWL Syntax
Date: Wed, 12 Feb 2003 22:19:27 +0100

> 
> Peter asked for some motivation for the proposed changes.
> 
> Off-list it also been suggested that I should give an example or summary for 
> those who don't want to get into the detail.
> 
> The key goal is to replace the text of 4.2 of AS&S with something 
> + clearer, 
> + easier to implement, and 
> + more reliably correct.
> 
> 
> There are other orthogonal goals to do with illustrating alternatives on the 
> issues of RDF compatibility, xml:lang and rdf:XMLLiteral.
> 
> 
> As an example we will consider the following DL ontology under AS&S.
> 
> Ontology(
>   EquivalentClasses(
>      restriction( dp1 cardinality(1) )
>      restriction( dp2 allValuesFrom( xsd:byte ) )
>      restriction( dp3 cardinality(1) )
>   )
> )
> 
> where dp1, dp2 and dp3 are datavaluedPropertyID's
> and xsd:byte is a well-known datatype.
> 
> Later we will consider the corresponding Ontology under the revised syntax.
> 
> Mapping this to triples we use
> 
> EquivalentClasses(description1 … descriptionn) 
> =>
> T(descriptioni) owl:sameClassAs T(descriptionj) . 1=<i<j=<n 
> 
> which is read in conjunction with "When the transformation of a component is 
> used as the subject or object of a triple, the transformation of the 
> construct is part of the production (but only once per production)" (see 
> section 4.1 of AS&S).
> 
> and we get the following triples
> 
> %  restriction( dp1 cardinality(1) )
> _:a rdf:type owl:Restriction .
> _:a owl:onProperty <dp1> .
> _:a owl:cardinality "1"^^xsd:nonNegativeInteger .
> 
> % dp1
> <dp1> rdf:type owl:DatatypeProperty .
> 
> % restriction( dp2 cardinality(1) allValuesFrom( xsd:byte ) )
> _:b rdf:type owl:Restriction .
> _:b owl:onProperty <dp2> .
> _:b owl:allValuesFrom xsd:byte .
> 
> 
> % dp2
> <dp2> rdf:type owl:DatatypeProperty .
> 
> %  restriction( dp3 cardinality(1) )
> _:c rdf:type owl:Restriction .
> _:c owl:onProperty <dp3> .
> _:c owl:cardinality "1"^^xsd:nonNegativeInteger .
> 
> % dp3
> <dp3> rdf:type owl:DatatypeProperty .
> 
> % EquivalentClasses
> _:a owl:sameClassAs _:b .
> _:a owl:sameClassAs _:c .
> _:b owl:sameClassAs _:c .
> 
> The difficulty here is that the bnode _:c is the object of two triples, one of 
> the very few places where this is permitted in the mapping rules of AS&S; but 
> it is only permitted when the owl:sameClassAs triples form a pattern that can 
> be generated by this mapping rule (e.g. deleting one but not two of these 
> triples moves the graph into OWL Full).

I don't believe that this is the case.  

 Ontology(
   EquivalentClasses(
      restriction( dp1 cardinality(1) )
      restriction( dp3 cardinality(1) )
   )
   EquivalentClasses(
      restriction( dp1 cardinality(1) )
      restriction( dp2 allValuesFrom( xsd:byte ) )
   )
 )

will generate a version with one owl:sameClassAs triple removed.

[...]

> 
> Jeremy

peter
Received on Tuesday, 25 February 2003 13:58:52 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:57:57 GMT