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Re: importing and entialment

From: Jos De_Roo <jos.deroo.jd@belgium.agfa.com>
Date: Wed, 23 Oct 2002 17:56:54 +0200
To: "Jeff Heflin <heflin" <heflin@cse.lehigh.edu>
Cc: Jonathan Borden <jonathan@openhealth.org>, www-webont-wg@w3.org, www-webont-wg-request@w3.org
Message-ID: <OF875E00BD.675E94FE-ONC1256C5B.005187B8-C1256C5B.00579C35@agfa.be>


[...]

> I'd rather not tell developers exactly how they must treat an import
> failure. The beauty of the "A imports B means anything entailed by B is
> also entailed by A" semantics of imports is that developers can decide
> for themselves how to handle an imports failure, whether it be by error
> condition (as Jeremy seems to desire) or by special triples on success
> (as you suggest). The only requirement the proposed semantics enforce is
> that if the imports fails, a system cannot claim to have deduced the
> complete set of inferences from the document.

so we could say that

==== http://www.w3.org/2002/03owlt/SocratesP
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix : <SocratesP#> .

<> owl:imports <SocratesA> .
:Socrates a :Man .
====


has an owl:imports of

==== http://www.w3.org/2002/03owlt/SocratesA
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix : <SocratesP#> .

:Man rdfs:subClassOf :Mortal .
====


and owl entails

==== http://www.w3.org/2002/03owlt/SocratesC
@prefix : <SocratesP#> .

:Socrates a :Mortal .
====


and not being able to give e.g. a proof for that
is incomplete


> As a sidebar, for those of you who are not so familiar with the
> terminology of logic, here's what is meant by "complete":
>
> ENTAILMENT is a theoretical notion that describes what can be deduced
> from a set of statements using the semantics of a specific logic.
> Entailment can be used to verify the correctness of inference engines /
> deductive systems. If the inference engine can deduce all of the
> ENTAILED statements, then it is said to be COMPLETE. If it does not
> deduce any statements that are not entailed, then it is said to be
> SOUND.

nice (pointer?)
it seems to be consistent with
http://lists.w3.org/Archives/Public/www-archive/2002Oct/att-0049/02-owl-test-cases.html#runningReasoner

-- ,
Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Wednesday, 23 October 2002 11:58:10 GMT

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