W3C home > Mailing lists > Public > www-rdf-interest@w3.org > January 2002

Re: extend rdfs:Class & rdf:Property

From: Arjohn Kampman <akam@aidministrator.nl>
Date: Fri, 11 Jan 2002 11:07:42 +0100 (MET)
Message-Id: <200201111007.LAA00542@spa.aidministrator.nl>
To: alexaki@ics.forth.gr
Cc: www-rdf-interest@w3.org
Sofia Alexaki wrote:
> Hello,
> 
> The 11th rule in the RDF Model Theory which states that if
> xxx rdfs:subClassOf yyy   and aaa rdf:type xxx .
> then aaa rdf:type yyy
> does this rule applies if xxx is subclass of  rdfs:Class?
> 
> More precisely, if the following facts are stated:
> the  class MyClass is subClassOf rdfs:Class and C1 is instance of  MyClass
> i.e.,
> <rdfs:Class rdf:ID="MyClass">
> <rdfs:subClassOf
>   rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class"/>
> </rdfs:Class>
> 
> <MyClass rdf:ID="C1"/>
> 
> can I infer that C1 is a class? Or it is should be explicitly stated in
> the RDF file that C1 is instanceof rdfs:Class?
> 
> Repsectively, if I define a class MyProperty as subclass of rdf:Property
> and P1 is instance of MyProperty i.e.,
> 
> <rdfs:Class rdf:ID="MyProperty">
> <rdfs:subClassOf 
rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Property"/>
> </rdfs:Class>
> 
> <MyProperty rdf:ID="P1"/>
> can I infer that P1 is a property?

In my opinion, this inferencing is correct. This kind of inferencing could be
very useful to make richer languages as much backwards compatible with RDF
Schema as possible. If, for some reason, such a language defines its own
Class-primitive and declares it to be an rdfs:subClassOf rdfs:Class, RDF
Schema-only software will still be able to at least partially understand data
that uses this language (i.e. to detect the classes in the data).

Arjohn

--
arjohn.kampman@aidministrator.nl
aidministrator nederland b.v.  -  http://www.aidministrator.nl/
prinses julianaplein 14-b, 3817 cs amersfoort, the netherlands
tel. +31-(0)33-4659987   fax. +31-(0)33-4659987
Received on Friday, 11 January 2002 05:13:11 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:51:52 GMT