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Re: OWL2 RDF mapping and skolemization [was Re: OWL equivalentClass question]

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Sun, 15 Jul 2012 20:50:54 -0400
Message-ID: <5003656E.2000103@gmail.com>
To: David Booth <david@dbooth.org>
CC: Pat Hayes <phayes@ihmc.us>, Alan Ruttenberg <alanruttenberg@gmail.com>, Michael Schneider <schneid@fzi.de>, semantic-web@w3.org, nathan@webr3.org

On 07/15/2012 07:10 PM, David Booth wrote:
> Hi All,
>
> Thanks for your comments.  To get to the crux of the matter . . .
>
> On Fri, 2012-07-13 at 23:35 -0500, Pat Hayes wrote:
>> [ . . . ] If you start with a graph G contaning a bnode and skolemize
>> it to get another graph GS where the bnode has been replaced by a URI,
>> then G does not [necessarily] entail GS.
> Unless we're making a closed world assumption, that sounds wrong to me,
> because giving a (guaranteed new) name to a previously unnamed node is
> merely *adding* information -- no information has been removed -- so all
> previous entailments should still hold.  If the semantics are not
> currently defined that way then it seems to me that we've made a
> mistake.

Umm, you probably should step back a bit here and reflect on what you are saying.

You are saying that if have some information (G) and add some information to 
it (GS) then the lesser information (G) should entail the greater (GS).   This 
is not how entailment works.

peter
Received on Monday, 16 July 2012 00:51:24 UTC

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