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Re: Latest iteration of RDF Datatyping WD (ship it!)

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Wed, 17 Apr 2002 17:42:35 -0500
Message-Id: <p0510150db8e3a98b9594@[65.217.30.94]>
To: Patrick Stickler <patrick.stickler@nokia.com>
Cc: Jos De_Roo <jos.deroo.jd@belgium.agfa.com>, w3c-rdfcore-wg@w3.org
>On 2002-04-16 15:12, "ext Jos De_Roo" <jos.deroo.jd@belgium.agfa.com> wrote:
>
>>
>>  [...]
>>
>>>  I'm still wondering about the necessity of 2b. It's not
>>>  quite as troublesome to me as e.g. inferring a datatype
>>>  property idiom from an inline idiom, but I'm still not
>>>  sure it is essential.
>>>
>>>  Can you clarify for me what breaks if it is removed?
>>
>>  well, it's just that
>>  entailing
>>
>>  <http://example.org/dt#Jenny> <http://example.org/dt#age> _:z .
>>  _:z <http://www.w3.org/2001/XMLSchema#number> "35" .
>>
>>  out of
>>
>>  ( <http://www.agfa.com/w3c/n3/p7.nt>
>>  <http://www.agfa.com/w3c/n3/p7s.nt> )
>>
>>  seems ok to me
>>  but it's not that something would break of course
>
>Then, in the spirint of Occam and keeping the set of
>closure rules to the bare minimum necessary to capture
>the essential semantics, I'll leave it out.
>
>Is that OK with you, Pat?

Hmmm, good question. 2b does seem *valid* and it doesn't follow from 
the others (does it?) so it did ought to be in a complete set of 
closure rules. Of course that shouldn't be taken to mean that one has 
to use it on every occasion, but it should be stated in the document 
somewhere.

I guess I didn't spend too much time worrying about getting the 
closure rule set 'right' since it can't completely capture the idea 
of datatype entailment in any case, so it didn't seem to be so urgent 
as it was for RDFS, since there isn't going to be a 
datatype-entailment lemma. But let me think about that a bit more. 
Maybe there could be.

Pat


>
>>
>>>  Also, if 2b is present, then 2a is unnecessary, since
>>>  the rdf:type of ?o can then be inferred from the
>>>  rdfs:domain of ?d.
>>
>>  right, ok, will do that
>
>But now, in the absence of 2b, 2a is needed. What it
>really boils down to is a choice between 2a or 2b, and
>2a seems the more conservative.

True, but its not clear that is a good thing when giving closure 
rules. The empty set of rules is always a good conservative choice :-)

Pat


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Received on Wednesday, 17 April 2002 18:42:40 EDT

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