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RE: Possible semantic bugs concerning domain and range

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Fri, 18 Oct 2002 10:44:41 +0200
To: "Dan Connolly" <connolly@w3.org>, "Jos De_Roo" <jos.deroo.jd@belgium.agfa.com>
Cc: "Ian Horrocks" <horrocks@cs.man.ac.uk>, "Pat Hayes" <phayes@ai.uwf.edu>, <www-webont-wg@w3.org>
Message-ID: <BHEGLCKMOHGLGNOKPGHDEEGICAAA.jjc@hpl.hp.com>


>
> Oohh; that's quite compelling... currently, you can
> implement a complete RDFS reasoner with a
> horn/datalog reasoner. If we changed range to IFF,
> it's not clear that this property would hold.
>
> Likewise for subClassOf.
>

There is nothing wrong IMO in having OWL take a stronger view of RDFS
semantics than RDFS.

I am coming round to iff semantics on all these things in OWL. We realise
that many implementions will be incomplete, but then the role of Large OWL
semantics is to give an abstract idea of the meaning.

I think that test case

http://lists.w3.org/Archives/Public/www-archive/2002Sep/att-0227/00-owl-test
-cases.html#proposedTriplesIssue-I5.3-Semantic-Layering004

is compelling as part of the semantics of range

[[

_:jARP3358 rdf:type owl:Thing .
_:jARP3359 rdf:type owl:Restriction .
_:jARP3359 owl:onProperty second:prop .
_:jARP3359 owl:allValuesFrom second:A .
_:jARP3358 rdfs:subClassOf _:jARP3359 .

is-equivalent-to

second:prop rdf:type owl:Property .
second:prop rdfs:range second:A .

]]

but then we don't expect any reasoner to find everything.

In RDFS however, I think it is important that complete reasoners are easy to
write.
Hence my disquiet at putting the rdf:List semantics in RDF (and not in OWL)
cf:
http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Oct/0081.html


The OWL audience needs to be semantically sophisticated, and to understand
that there is a difference between what the spec says is "true" and what the
implementation they use can "prove". Hence, arguments from implementation
difficulty seem to me to indicate the need for annotations in the Test Cases
to manage user expectations (downwards).

Jeremy
Received on Friday, 18 October 2002 04:45:04 GMT

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