- From: Natasha Noy <noy@stanford.edu>
- Date: Thu, 2 Apr 2009 11:02:03 -0700
- To: Sw Fan <swfan1998@yahoo.com>
- Cc: public-swbp-wg@w3.org
Dear Mark,
I think you are right -- we didn't technically need the first
statement as any class is by definition a subclass of itself. It
doesn't hurt to have it there as it makes things a bit more clear
(perhaps?)
Natasha
On Mar 27, 2009, at 2:09 AM, Sw Fan wrote:
> Dear all,
>
> I've a question about the example for the Approach 1 in Representing
> Classes As Property Values on the Semantic Web. Below is the text
> extracted from the document:
>
> {{
>
> For instance, we may want to define a class of all books about
> animals—BookAboutAnimals—that
> our animal books will be instances of and we want to restrict the
> range of
> values for the dc:subject property for the BookAboutAnimals
> class to the class Animal and its subclasses. One way to define
> such restriction is as follows:
>
> :BookAboutAnimals
> a owl:Class ;
> rdfs:subClassOf :Book ;
>
> rdfs:subClassOf
> [ a owl:Class ;
> owl:unionOf ([ a owl:Restriction ;
> owl:onProperty dc:subject ;
> owl:hasValue Animal
>
> ]
> [ a owl:Restriction ;
> owl:onProperty dc:subject ;
> owl:someValuesFrom
> [ a owl:Restriction
> ;
> owl:onProperty rdfs:subClassOf;
> owl:hasValue Animal
> ]
> ])
>
> ] .
>
> }}
>
> My question is, why do we have to bother defining a union class
> above? Since a class is a subclass of itself, so from my
> understanding,
>
> [ a owl:Restriction ;
> owl:onProperty dc:subject ;
> owl:hasValue Animal
> ]
>
> has been subsumed by
>
>
> [ a owl:Restriction ;
> owl:onProperty dc:subject ;
> owl:someValuesFrom
> [ a owl:Restriction
> ;
> owl:onProperty rdfs:subClassOf;
> owl:hasValue Animal
> ]
> ]
>
>
> Is there anything I missed here? Thank you!
>
> Best,
> Mark
>
>
Received on Thursday, 2 April 2009 18:02:48 UTC