RE: intersectionOf and subClassOf

> -----Original Message-----
> From: www-rdf-logic-request@w3.org
[mailto:www-rdf-logic-request@w3.org]
> On Behalf Of Peter F. Patel-Schneider
> Sent: Monday, March 31, 2003 8:46 AM
> To: geoff@sover.net
> Cc: franconi@inf.unibz.it; www-rdf-logic@w3.org
> Subject: Re: intersectionOf and subClassOf
> 
> 
> [...]
> 
> > - A is a subClassOf B and C
> > - A is a subClassOf a class that is the intersectionOf B and C
> > - A is a subClassOf a class that is the intersectionOf B and a class
> > that is the intersectionOf C
> > - A is a subClassOf a class that is a subClassOf B and C
> > - ...
> 
> These all appear to say the same thing.  (It is a bit difficult to
state
> this categorically because you are not being very precise here.)

Can you clarify a related question for me? I'll try to be a bit more
precise this time :-) 

Given this situation:

<owl:Class rdf:about="X">
	<rdfs:subClassOf rdf:resource="B"/>
	<rdfs:subClassOf rdf:resource="C"/>
</owl:Class>

<owl:Class rdf:about="Y">
	<owl:intersectionOf rdf:parsetype="Collection">
		<owl:Class rdf:about="B"/>
		<owl:Class rdf:about="C"/>
	</owl:intersectionOf>
</owl:Class>

It seems to me that we can know:

<rdf:Description about="X">
	<rdfs:subClassOf rdf:resource="Y"/>
</rdf:Description>

but not:

<rdf:Description about="X">
	<owl:equivalentClass rdf:resource="Y"/>
</rdf:Description>

Is that right? I'm assuming that we can take the description of Y as
complete due to the nature of rdf:List(s) but we can never know that the
description of X is complete (i.e. there could be another statement such
as:

<owl:Class rdf:about="X">
	 <rdfs:subClassOf rdf:resource="D"/>
</owl:Class>

lurking out there waiting to be found.

If that's right, I'm wondering about the related issue of restrictions.
There don't seem to be cardinality restrictions on onProperty, etc. so
I'm wondering how we can ever treat a restriction as complete? i.e. can
we ever infer that the class extensions of two restrictions are the
same?

Thanks,

Geoff Chappell

> 
> peter

Received on Monday, 7 April 2003 08:54:06 UTC