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Re: SEM: comprehensive entailments without dark triples

From: Jonathan Borden <jonathan@openhealth.org>
Date: Mon, 22 Apr 2002 13:13:13 -0400
Message-ID: <01cf01c1ea20$fd0857c0$0a2e249b@nemc.org>
To: "Dan Connolly" <connolly@w3.org>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>, <www-webont-wg@w3.org>
Dan Connolly wrote:

> On Mon, 2002-04-22 at 10:41, Peter F. Patel-Schneider wrote:
> > The problem with these comprehension principles is that they do not
> > generate non-tree structures.  Therefore classes that are not in the
form
> > of trees (yes, this is rather vague, but my previous message gives one
> > example) will not be consequences.
>
> I'm having a hard time seeing this as a problem.

I have a relatively easy time seeing why this would be a problem. (gasp,
perhaps this DL stuff is starting to slowly sink in...) This sort of issue
might arise frequently in genetics (for example) and I was really hoping
that the language would be able to make these sorts of inferences -- e.g.
going from facts about individuals (i.e. patients) to classes of diseases.

>
> This is the example from your message of
> 22 Apr 2002 11:29:50 -0400; that's the one you refer to, yes?
>
>      John rdf:type Person .
>      Bill rdf:type Person .
>      John child Bill .
> entailing
>      John rdf:type _:1 .
>      _:1 rdf:type daml:Restriction .
>      _:1 rdf:onProperty child .
>      _:1 rdf:hasClass :_1 .
>
>
> I can't understand it well enough to see why I would want
> it to be the case.
>
> By way of trying to relate this to some use case
> or requirement, here's an attempt at a sort of
> natural-language translation:
>
>   If John has a child, then John is in the class
>   of things that have children that are in this
>   class I'm talking about.
>
> It just looks like gobbledygook.
>
> It seems to me we can meet our requirements and
> users' expectations without this entialment holding.

Peter et al. were asked to give a concrete example illustrating the issue.
He has done that.

I imagine that this is just one of a likely infinite set of examples that he
could generate if he has the inclination. It might be a really long process
going through these, and if the set is really infinite, even after any
arbitrarily large amount of time and effort, we still won't be sure we've
excluded any problems.

> Am I missing something?
>

Are you sure you aren't?

Jonathan
Received on Monday, 22 April 2002 13:17:11 GMT

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