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Re: Restriction, DeprecatedClass in OWL Language Reference 31 March 2003

From: Richard H. McCullough <rhm@cdepot.net>
Date: Tue, 13 May 2003 14:01:41 -0700
Message-ID: <006401c31992$f6fb4d90$bd7ba8c0@rhm8200>
To: "Guus Schreiber" <schreiber@cs.vu.nl>
Cc: "webont-comments at W3C" <public-webont-comments@w3.org>

So your class hierarchy is

    rdfs:Class
        owl:Class
        owl:Restriction
        owl:DeprecatedClass

That raises several questions in my mind.
1. Shouldn't you strive for
    owl:Class  owl:sameAs  rdfs:Class
2. Shouldn't owl:Restriction be a metaclass of rdf:Property?
    owl:Restriction  rdfs:subClassOf  rdf:Property
3. Likewise, shouldn't these be subClasses of rdf:Property
     owl:DataRange
     rdfs:Datatype
     owl:DeprecatedProperty
     rdfs:Literal
4. It would be desirable to define an owl:Entity class,
disjoint from rdf:Property, which would include as subClasses
    owl:AllDifferent
    rdfs:Container
    owl:DeprecatedClass
    owl:Enumeration
    owl:Intersection
    rdf:List
    owl:Ontology
    owl:Union
5. The above would produce the Class hierarchy
    owl:Thing
        owl:Entity
        rdf:Property
        rdf:Statement
where Entity,Property,Statement are disjoint and exhaustive.
This hierarchy is very meaningful, from both  metaphysical
and epistemological viewpoints.
Entity is the class of primary things that exist.
Property is the class of Entity properties plus meta properties
    (properties of things other than entities).
Statement is the class of relations between things.

Dick McCullough
knowledge := man do identify od existent done;
knowledge haspart proposition list;

----- Original Message ----- 
From: "Guus Schreiber" <schreiber@cs.vu.nl>
To: "Richard H. McCullough" <rhm@cdepot.net>
Cc: "webont-comments at W3C" <public-webont-comments@w3.org>
Sent: Monday, May 12, 2003 3:32 AM
Subject: Re: Restriction, DeprecatedClass in OWL Language Reference 31 March
2003


> Richard H. McCullough wrote:
>
> > Appendix B declares two Classes (Restriction, Deprecated Class)
> > to be subClasses of Class.
> >
> > <rdfs:Class rdf:ID="Restriction">
> >   <rdfs:label>Restriction</rdfs:label>
> >   <rdfs:subClassOf rdf:resource="#Class"/>
> > </rdfs:Class>
> > <rdfs:Class rdf:ID="DeprecatedClass">
> >   <rdfs:label>DeprecatedClass</rdfs:label>
> >   <rdfs:subClassOf rdf:resource="&rdfs;Class"/>
> > </rdfs:Class>
> >
> > I think this is an error.
> > If it's not an error, what is the explanation?
>
> Thanks for your comment.
>
> We do not think it is an error. These are built-in metaclasses, the
> instances of which are classes. Thus, owl:Restriction and
> owl:DeprecatedClass are defined as a subclass of the general metaclass
> rdfs:Class (owl:Class is a subclass of rdfs:Class).
>
> Please let us know whether this response is satisfactory.
>
> Guus Schreiber
Received on Tuesday, 13 May 2003 17:02:23 GMT

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