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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  

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?

Received on Monday, 23 January 2006 17:29:19 UTC

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