Re: subclass loops, proper subclasses and so on

From: pat hayes (
Date: 08/28/01

>Pat wrote:
> > 1. What reason can there be to forbid subclass loops, other than
> > subClassOf being understood to mean proper subclass?
>The two issues are not completely tied together it seems to me,
>since it would be completely coherent to forbid subclass loops, 
>while still allowing non-proper subclasses (in fact, this is the way 
>I have been reading the RDF Schema spec until now (and many with 

Well, marginally coherent. My second point was that there could be no 
*justification* for that reading. If someone was using the other, 
proper-subclass, reading, they would make exactly the same inferences 
that you would. So there is nothing in the actual semantics to 
justify the 'allowing' of nonproper subclasses if loops are forbidden.

>So yes, if you want only proper subclasses, you must forbid loops,
>but this would seem to me to be the wrong decision on two counts,
>while the position of forbidding loops but allowing non-proper subclasses
>would still be coherent, and be wrong on only one count.
>(no prices for guessing what my favourite position on both these 
>issues would be...)

Well, maybe we can persuade the RDF Core WG to see the light.


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