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Re: model theory publication draft

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Wed, 19 Sep 2001 13:02:57 -0500
Message-Id: <p0510101db7ce8ab45a78@[]>
To: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Cc: w3c-rdfcore-wg@w3.org
>At 02:27 PM 9/18/01 -0500, Pat Hayes wrote:
>>At last the model theory is in readable form, at
>I have a couple of small comments/questions about this, and a more 
>substantial issue (the final point below).
>- the document variously uses the terms URI, uriref, <uriref> to 
>mean something like "URI-plus-optional-fragment".  Maybe we could 
>coin a term for this and use it consistently?

I await instruction. I meant to use 'URI' as the vanilla terminology, 
and 'uriref' when referring to Ntriples, but I may have slipped up in 

>- Section 5:
>I thought this was great;  very neat.  Would I be correct in 
>thinking that the schema-closure of any graph satisfies the Strong 
>Herbrand Lemma.
>Hmmm.. as stated, I think this is trivially true, as the lemma is 
>stated in terms of satisfaction, which is not affected by the new 
>inferences based on schema constructs.


>I think what I want to suggest is this version of the lemma:
>   The schema-closure of any RDF graph has an RDFS interpretation 
>that satisfies the graph and does not satisfy any ground triple not 
>in the graph.

Hmm, that seems right, but let me think about it. There are probably 
several neat results like this for RDFS which I simply haven't 
thought of.

>>>>  the substantial issue:
>- Section 5:
>I think there may be a problem with the schema lemma,

>The problem, I think, is that the schema closure is applied before 
>doing the graph merge.  I think the lemma should be something like 
>   S s-entails E iff the schema-closure of the merge of members of S entails E.

YES!  You are absolutely right!

Many thanks for catching this. I will fix this in the next version 
(ready in a few hours)

See, *this* is why one ought to write the proofs before publishing.


>Graham Klyne                    MIMEsweeper Group
>Strategic Research              <http://www.mimesweeper.com>

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Received on Wednesday, 19 September 2001 14:03:03 UTC

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