- From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
- Date: Fri, 16 Nov 2001 11:37:32 +0000
- To: Pat Hayes <phayes@ai.uwf.edu>
- Cc: w3c-rdfcore-wg@w3.org
It's almost a victim of its own beauty ;-)
I completely overlooked the section of graph merging when I responded,
partly because it was so short but mostly because I wasn't expecting it to
be in the section on entailment... (That's not much of an excuse really,
it is well-enough signposted in the document; oh well.)
Anyway, a simpler suggestion might be to simply move the definition of
graph merging up to section 0.2, just after the definition of tidiness?
#g
--
At 04:35 PM 11/15/01 -0600, Pat Hayes wrote:
>>At 09:03 AM 11/15/01 -0600, Dan Connolly wrote:
>>>No? Why not? How is it that you conclude that bnodes
>>>in different graphs are different? I don't see it stated
>>>in the model theory.
>>
>>It appears it's not stated directly, and probably should be since that
>>was (to me) clearly the intent of our discussions. Also, the final
>>sentence of this text from section 2.0 pretty clearly signals that intent:
>>
>>[[[
>>This effectively treats all unlabeled nodes as existentially
>>quantified in the RDF graph in which they occur. Notice that since
>>two nodes cannot have the same label, there is no need to specify
>>the 'scope' of the quantifier within a graph. (However, it
>>is local to the graph.) If we were to apply the semantics
>>directly to N-Triples syntax, we would need to indicate the
>>quantifier scope, since in this lexicalization syntax the same bNode
>>identifier may occur several times. The above rule amounts to
>>the N-triple convention that would place the quantifiers just
>>outside, i.e. at the outer edge of, the N-triple document
>>corresponding to the graph.
>>]]]
>
>The reason why this issue is treated rather elliptically in the MT is that
>the great merit of the graph syntax, as I see it, is that the issue simply
>*does not come up*. There are no quantifiers, no bound variables and no
>scopes to keep track of, it all works out automatically. The merging
>conditions are a joy to state (merge nodes required to be tidy, ie
>urirefs; don't merge anything else.) It's beautiful. It seemed perverse to
>introduce the clunky logical notation only to be able to say that we don't
>have those problems.
>
>If people feel that this issue should be aired more thoroughly, I would
>suggest that I write a slightly fuller account of how the graph syntax
>makes local scoping unnecessary, maybe with a couple of examples, and put
>it into the 'mapping into logic' section, and then refer to that from
>elsewhere in the document as needed. Any objections/comments?
>
>Pat
>
>--
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Received on Friday, 16 November 2001 07:36:33 UTC