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Two small corrections (Re: Punning, typed vocabulary, and handling RDF graphs (and ISSUE-65))

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Thu, 10 Jan 2008 11:51:25 +0000
Message-Id: <E8A6EE8B-CB27-4EAA-A952-88C49BEC81C8@cs.man.ac.uk>
Cc: "Web Ontology Language ((OWL)) Working Group WG" <public-owl-wg@w3.org>
To: Bijan Parsia <bparsia@cs.man.ac.uk>

Thanks to Boris for pointing these out:

On Jan 10, 2008, at 12:31 AM, Bijan Parsia wrote:
[snip]
> G2
> 	:C rdf:type owl:Class.
> 	:p rdf:type owl:DatatypeProperty.
> 	:q rdf:type owl:ObjectProperty.
> 	:D rdf:subClassOf [a Restriction;
> 		onProperty :p;
> 		someValuesFrom :C]
> 	:E rdf:subClassOf [a Restriction;
> 		onProperty :q;
> 		someValuesFrom :C]
>
> This is not in OWL DL and cannot be repaired to be. The reason is  
> that in the axiom about :E, :C needs to be a datatype.

This should read, "The reason is that in the axiom about *:D*..."

[snip]
> 	This is why we have owl:11ObjectRestriction and  
> owl11:DataRestriction. Note that this a *syntax* flaw because we  
> cannot make the value of an onProperty (or somevaluesfrom)  
> "locally" typed.
[snip]

What I mean is that ObjectRestriction and DataRestriction were  
introduced to handle a fundamental syntax flaw (or feature) of  
RDF...nodes have no context, so you can't specify context specific  
things. So you can't say, "In this restriction, we're talking  
datatypes, and in this one, classes" without reification. The XML  
syntax, for example, doesn't have this problem.

Cheers,
Bijan.
Received on Thursday, 10 January 2008 11:51:42 GMT

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