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One semi-historical point (was Re: ISSUE: DISTINCT is underspecified)

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Thu, 17 Aug 2006 10:57:16 +0100
Message-Id: <2F6E5161-5D97-4853-816F-DFE09ABA5959@cs.man.ac.uk>
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>
To: Pat Hayes <phayes@ihmc.us>

On Aug 17, 2006, at 8:34 AM, Pat Hayes wrote:
[snip]

> Well, this is an aside to our main discussion here, but I think  
> that it would be quite acceptable to have an RDF query standard  
> which was defined *entirely* syntactically, and simply treated an  
> RDF graph as a triple store, and used essentially algebraic  
> operations to troll through it for patterns that match and satisfy  
> superficial conditions (which might include semantic conditions if  
> those can be computed locally, eg typed literal values). This was  
> basically the design we had originally, about which so many  
> protests were received wanting a more 'semantic' account.

I think is a point of misunderstanding. If y'all said, "We're  
defining the Query Of RDF Syntax (QORS) language, and if you want to  
do simple, or rdf, or rdfs, with or without D, or even OWL, well,  
you're out of luck, make a new standard and you might consider  
borrowing our query  language syntax" I would not have objected. Or  
at least not in the same way. I'm fine without a unitary semantic  
framework per se. Just let me *say* in my own way, what the semantics  
are (ok, some framework would be nice, just to make them easier to  
read; but I'm fine with an outlier), and give me good hooks to  
indicate when I'm using it (and the hooks should be in the query  
language please; not all sparql query is across the web in any  
interesting way).

What I objected to was 1) a syntactic reading that in no way tied to  
the RDF Semantics document, and 2) the claim that this would require  
no change in order to work for simple, rdf, rdfs, and even OWL  
queries. This is manifestly not true. There are people in the working  
group who support RDFS, and at the very least you have to say  
something about contradictory documents. Even if you go with maximal  
consistent subsets, that still needs to be said, explained, etc. So  
my problem then is the same as my problem now: Lots of things are  
unspecified or underspecified. Some of the offered ways of specifying  
just would work very well if at all.

>>  And I think we should make the semantics available. (Now, of  
>> course, we're disagreeing on what the semantics require. Let me  
>> weaken my principle to say that it should help people understand  
>> the semantics of the graph.)
>
> OK, Im quite happy with that reading. But I still think that its  
> important to not suppress answers which can be used to extract  
> *semantically* distinct information entailed by the graph. I guess  
> my point is that it is the semantics of the *graph*, not of the  
> *answers*, that likely matter most to a querying agent.

Well, we disagree. Or at least, I think focusing the semantics of the  
answers are:
	1) important
	2) reasonable
	3) easier to specify, understand, and implement

This doesn't mean I feel a need to kick yours out, but if there's  
only one, yeah, this is the one I'll support.

Cheers,
Bijan.
Received on Thursday, 17 August 2006 09:57:45 GMT

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