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RE: SEM: circular primitive

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Tue, 23 Apr 2002 05:51:21 -0400
To: jjc@hplb.hpl.hp.com
Cc: connolly@w3.org, jonathan@openhealth.org, www-webont-wg@w3.org
Message-Id: <20020423055121T.pfps@research.bell-labs.com>
From: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>
Subject: RE: SEM: circular primitive 
Date: Tue, 23 Apr 2002 10:20:10 +0100

[...]

> Showing that I am still playing the game according to my preferred
> rules of discussing concrete cases in sufficient, but hopefully
> not exhaustive detail, let us consider Peter's child case.
> 
> (In this case I fear it is exhausting but not exhaustive!)
> 
> > R:
> > 

KB1:
> >      John rdf:type Person .
> >      Bill rdf:type Person .
> >      John child Bill .

> > entailing

KB2:
> >      John rdf:type _:1 .
> >      _:1 rdf:type daml:Restriction .
> >      _:1 rdf:onProperty child .
> >      _:1 rdf:hasClass :_1 .

> I personally think this, as stated, is false. But like Jonathan
> I think it points to an important use case, for which I will give
> my treatment.

> I think R is false because:
>   If R is true then the premises also entail that

KB3:
>   Bill rdf:type _:1 .

Please explain.  It is true that KB1 entails KB3, of course, because, there
is a type for Bill, namely Person.  However, how can KB1 entail KB2 plus
KB3 (taken as a single graph)?  Bill does not have a child, so he does not
satisfy the conditions on _:1 in KB2.

> and hence
>   
>   Bill child _:x .
>   _:x rdf:type _:1 .
> 
> and I do not think that the premises should license the first triple 
> of such a conclusion.

peter
Received on Tuesday, 23 April 2002 05:52:49 GMT

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