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Re: Comments on RDF Schema specification

From: Pierre-Antoine CHAMPIN <champin@bat710.univ-lyon1.fr>
Date: Wed, 14 Jun 2000 17:42:00 +0200
Message-ID: <3947A7C8.122BEA69@bat710.univ-lyon1.fr>
To: Michel Klein <mcaklein@cs.vu.nl>, www-rdf-comments@w3.org
Michel Klein wrote:
> First, there was no way to overcome the restriction on the rdfs:subClassOf
> statement, i.e. the restriction that no cycles are allowed in the
> subsumption hierarchy.

yes, there is :
define a property oil:subClassOf which is a SUPERPROPERTY of rdfs:subClassOf,
and which allows cycles !
You can still use rdfs:subClassOf if you know for sure that 2 classes are not equivalent,
but if you are unsure (that is, if a cycle MAY occure), use oil:subClassOf.

it's just an idea, anyway... I agree with you that rdfs:subClassOf SHOULD accept cycles ;-)

> Second, in contrast with RDFS, OIL allows more than one range restriction
> on a property.

this would be nice too, I agree.

I think RDFS was designed with the idea of allowing schema-validation,
that's why RDFS properties are over-constraining. (subClassOf, range...)
Note the post from Ralph Swick suggesting to disallow multiple domains...
In an open world hypothesis, allowing multiple constraint properties make them no more constraining, only indicative... that does not bother me, but it seems to bother Ralph.


--- Quid quid Latine dictum sit, altum viditur
    Whatever is said in Latin sounds important.
Received on Wednesday, 14 June 2000 11:43:02 UTC

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