- From: Brian McBride <bwm@hplb.hpl.hp.com>
- Date: Fri, 25 Oct 2002 09:46:03 +0100
- To: "Jos De_Roo" <jos.deroo.jd@belgium.agfa.com>
- Cc: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>, "pat hayes" <phayes@ai.uwf.edu>, w3c-rdfcore-wg@w3.org, w3c-rdfcore-wg-request@w3.org
At 10:28 25/10/2002 +0200, Jos De_Roo wrote:
>I guess it's the one from
>http://lists.w3.org/Archives/Public/www-webont-wg/2002Sep/0308.html
>
>1:[[
>
>eg:prop rdfs:range eg:A .
>eg:A rdfs:subClassOf eg:B .
>
>entails
>
>eg:prop rdfs:range eg:B .
>]]
Which looks clearly false to me, so I'd better ask to find out what I'm
missing.
Consider:
IEXT(A) = {a}
IEXT(B) = {a, b}
Then if I say that prop can take any member of A as its value, it can also
take any member of B, because B happens to be a superclass of B.
Wierd!
Isn't it to stop that sort of thing happening that we switched domain and
range to conjunctive semantics, i.e. so that an inferencing engine finding
a range constraint would know that all values must be a member of that
class; there is no way to add members to the range?
Brian
Received on Friday, 25 October 2002 04:43:33 UTC