RE: "Is a Property a Class" and other DAML questions

I was not using `` and '' as string quotes.  For that, " would be
appropriate.  I was instead using `` and '' as a mechanism to distinguish
between the English word Property and the object defined in DAML that has
the ID Property.  I'll rephrase all that more pedantically.


This [the fragment in question] says that the resource with URI
daml:Property has rdf:type rdfs:Class, i.e., that the triple <rdf:type,
daml:Property, rdfs:Class> is in the base of DAML+OIL, which is very
different from saying that a resource that has rdf:type daml:Property is a
class.


A triple that would sort of have the effect of making properties
classes would be <rdfs:subClassOf, daml:Property, rdfs:Class>, which makes
the resource with URI daml:Property a subclass of rdfs:Class.  In the
(informal) intended meaning for RDFS this has the result of making any
resource that has daml:Property among its values for rdf:type also have
rdfs:Class among its values for rdf:type, i.e., making properties classes.

Peter Patel-Schneider


From: "Hart, Lewis" <lhart@grci.com>
Subject: RE: "Is a Property a Class" and other DAML questions
Date: Thu, 8 Mar 2001 08:47:09 -0500 

> I don't mean to be dense but, the definition of sameClassAs is...
> 
> <rdf:Property ID="sameClassAs">
>   <rdfs:comment>
>     for sameClassAs(X, Y), read X is an equivalent class to Y.
>     cf OIL Equivalent
>   </rdfs:comment>
>   <rdfs:subPropertyOf rdf:resource="#equivalentTo"/>
>   <rdfs:subPropertyOf
> rdf:resource="http://www.w3.org/2000/01/rdf-schema#subClassOf"/>
> </rdf:Property>
> 
> So taking the comment and applying it to the Property statement below...
> 
> for sameClassAs(Property,
> http://www.w3.org/1999/02/22-rdf-syntax-ns#Property)
>   Property is an equivalent class to
> http://www.w3.org/1999/02/22-rdf-syntax-ns#Property.
> 
> Which is treating http://www.w3.org/1999/02/22-rdf-syntax-ns#Property as a
> class, and if this
> is not a property, then what is?
> 
> It seems to me that when you refer to something whose ID is "Property" it is
> 
> the object/resource/class identified as a property. You are not saying that
> the string
> "Property" is a class. (Even though it may be.)
> 
> 
> 
> -----Original Message-----
> From: Peter F. Patel-Schneider [mailto:pfps@research.bell-labs.com]
> Sent: Wednesday, March 07, 2001 6:15 PM
> To: lhart@grci.com
> Cc: www-rdf-logic@w3.org
> Subject: RE: "Is a Property a Class" and other DAML questions
> 
> 
> This says that ``Property'' is a class, which is very different from saying
> that a property is a class (or, equivalently, that properties are classes).
> 
> peter
> 
> 
> From: "Hart, Lewis" <lhart@grci.com>
> Subject: RE: "Is a Property a Class" and other DAML questions
> Date: Wed, 7 Mar 2001 16:00:58 -0500 
> 
> > Perhaps the implication is coming from this statement in the DAML+OIL
> spec: 
> > 
> > <rdfs:Class rdf:ID="Property">
> >   <sameClassAs
> > rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Property"/>
> > </rdfs:Class>
> > 
> > I am not an RDF(S) expert, but to me this says that a Property is a Class.
> > If this is not the case, what point am I missing?
> > 
> > - Lewis
> > ___________________________________________
> > Lewis L Hart 
> > GRC International                           lhart@grci.com
> > 1900 Gallows Rd.                  Voice (703)506-5938
> > Vienna, Va 22182                    Fax (703)556-4261

Received on Thursday, 8 March 2001 10:16:06 UTC