Re: [LC response] To Richard H. McCullough

No, I am not satisfied with your proposed additional text.

If  OWL2 "class" is the "extension set" of a "concept",
your document should say that.

If your document does not say that, you are missing
this unique opportunity to eliminate the confusion
associated with RDF "class".

I propose adding the text below as the first paragraph
of section 4 of the OWL2 primer.

Natural languages use a "concept" to refer to a group
of similar, individual entities.  A "concept" may be
defined by its
    "extension" -- the set of all individual entities
                        which are members of the group
    "genus" -- the more general group which includes
                   all individual members of the group
    "differentiae" -- the properties [a.k.a. "intension"]
                          which are shared by all individual
                          members of the group, and which
                          distinguish them from other members
                          of the "genus".
In OWL 2: 
    a "class" is the "extension set" of a "concept";
    the "class" is a "subClassOf" the "genus class";
    property "restrictions" specify the "differentiae".

Dick McCullough

----- Original Message ----- 
From: "Sebastian Rudolph" <>
To: <>
Cc: <>
Sent: Wednesday, May 13, 2009 10:41 AM
Subject: [LC response] To Richard H. McCullough

> Dear Richard,
> Thank you for your comment
>      < 
> >
> on the OWL 2 Web Ontology Language last call drafts.
> In order to avoid any possible confusion we have added some text to  
> the OWL 2 Primer that clarifies the meaning of class and the  
> correspondence with concept (see < 
> >).
> As a historical remark, the use of "class" in OWL 2 comes from its  
> prior use in related representation systems. RDF uses "class" (as  
> opposed to "concept" or another term). The original version of OWL  
> uses "class" to be compatible with RDF.
> Please acknowledge receipt of this email to < 
> > (replying to this email should suffice). In your acknowledgment  
> please let us know whether or not you are satisfied with the working  
> group's response to your comment.
> Regards,
> Sebastian Rudolph
> on behalf of the W3C OWL Working Group
> _________________________________________________
> Dr. Sebastian Rudolph
> Institute AIFB, University of Karlsruhe, D-76128 Karlsruhe
>    phone +49 (0)721 608 7362
>                 fax +49 (0)721 608 5998

Received on Wednesday, 13 May 2009 20:02:21 UTC