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Re: Editorial thread for BGP matching

From: Enrico Franconi <franconi@inf.unibz.it>
Date: Mon, 23 Jan 2006 18:29:14 +0100
Message-Id: <E78D2A4F-0686-447F-9299-E7A8C1036D11@inf.unibz.it>
Cc: Andy Seaborne <andy.seaborne@hp.com>, RDF Data Access Working Group <public-rdf-dawg@w3.org>
To: Pat Hayes <phayes@ihmc.us>

On 23 Jan 2006, at 18:17, Pat Hayes wrote:
>> "In the case of simple entailment, if the scoping graph G' is such  
>> that it does not share blank nodes with BGP, then the above  
>> definition can be simplified to take the union between G' and BGP,  
>> instead of an OrderedMerge."
>
> This works for any kind of entailment, which is why I prefer the  
> simpler wording: and then we don't need this odd notion of ordered  
> merging at all. In fact, I'd suggest that the simpler wording  
> should be normative, as it expresses the intended meaning more  
> directly and straightforwardly. Also, it keeps distinct issues  
> separate. Exactly how an engine handles bnode scoping (what gets re- 
> written, or maybe use hash-tables, whatever) really is an  
> implementation decision. We shouldn't build into the entailment  
> clause what is in effect an implicit decision about how to  
> implement bnode scoping.

This is not about irrelevant stuff, this is about being precise and  
non-ambiguous.

We have to be as precise as possible when writing down a definition,  
and not leave it to the verbal part.

That's why I am proposing to have *my* precise definitions, and  
adding a verbal part explaining with *your* simpler wording: since  
they are equivalent for simple entailment, everybody is happy.

I repeat that we need all the ingredients in the spec, since they  
allow us to introduce a terminology that future user have to refer to  
in order to make their choices - if they want to say that they are  
(backward) compatible with SPARQL. Future implementors have to  
declare, for example, what is their kind of entailment *and* their  
scoping set B, since they are in the spec.

So again, why don't you like my proposal of having precise  
definitions with the simple wording explaining them?

--e.
Received on Monday, 23 January 2006 17:29:19 GMT

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