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Re: Proposal and Test cases (Re: skolems: visible differences?)

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Wed, 16 Jan 2008 13:58:11 +0000
Message-Id: <8CC8C5F9-8AA1-41CD-9390-B4F58D654367@cs.man.ac.uk>
Cc: OWL Working Group WG <public-owl-wg@w3.org>
To: Jeremy Carroll <jjc@hpl.hp.com>

On 16 Jan 2008, at 13:25, Jeremy Carroll wrote:

> Bijan Parsia wrote:
>
>>> TEST 5:
>>>     ObjectPropertyAssertion(:p :x _:y)
>>>
>>> does not entail
>>>
>>>     ObjectPropertyAssertion(:p :x _:y)
>
>> One can mitigate the surprise of test 5 by allowing users to set  
>> the scope of the bnode ids
>
> I prefered earlier blurb where you talked about renaming the bnodes  
> (in this case with the identity function)
>
> earlier text: [[
> The solution, I think, is to point out that one is permitted to  
> substitue individualNames for fresh individualNames without  
> changing the meaning of an ontology.
> ]]

I said that? Well, makes sense :)

The take away, I guess, is that there are Other Things happening  
besides the core entailment relation. This has always been true but  
the boundaries shift around. (E.g., what *were* BNodes in RDF M&S? Hmm:
	http://www.w3.org/TR/1998/WD-rdf-syntax-19981008/
Wow...v. old school W3C specs...if you look at the discussion around  
figures 2 and 3, it seems that we are closer to the skolem  
interpretation in that blank nodes are *singular*, not (potentially)  
plural. That said, it took me two seconds to find an inconsistency:
	""""Resources are always named by URIs plus optional anchor IDs (see  
[URI]).""""
	"""The sentence above does not give a name to that resource; it is  
anonymous, so in the diagram below we represent it with an empty  
oval...Note that this diagram is identical to the previous one with  
the addition of the URI for the previously anonymous resource."""

I don't retroactively envy the members of RDF core :))

>>> TEST 6:
>>>     ObjectPropertyAssertion(:p :x _:y)
>>>     ObjectPropertyAssertion(:p :x :z)
>>>     ClassAssertion( :p ObjectExactCardinality( 1, :x ) )
>>>
>>> is consistent
>
> This test was motivated because it wasn't clear to me that your  
> definition said this. As long as its meant to say this, then I am  
> happy at this stage, (it's more important to understand the intent  
> than the actual text right now)

Yep. Cool.

Cheers,
Bijan.
Received on Wednesday, 16 January 2008 13:56:21 GMT

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