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Re: comments on SPARQL Query Language for RDF

From: Lee Feigenbaum <feigenbl@us.ibm.com>
Date: Tue, 5 Jun 2007 14:12:35 -0400
To: Bob MacGregor <bmacgregor@siderean.com>
Cc: public-rdf-dawg-comments@w3.org
Message-ID: <OFA7AA84D5.E159EC05-ON852572F1.005F5606-852572F1.006405CD@us.ibm.com>

Hi Bob,

Bob MacGregor <bmacgregor@siderean.com> wrote on 06/04/2007 09:49:45 PM:

> Hello Lee,
> 
> On Jun 4, 2007, at 1300, Lee Feigenbaum wrote:
> 
> Bob MacGregor wrote on 05/31/2007 07:52:26 PM:
> 
> My argument is against the choice of an algebraic semantics instead 
> of a declarative
> semantics.  Unless I am mistaken, OWL has a declarative semantics, and I
> would assume that SWIRL and RuleML have or will each have a 
> declarative semantics.
> Suppose X would like to implement rules from one of these languages 
using
> SPARQL to evaluate the rule bodies.  If the semantics of SPARQL aligns 
with
> the rule language, or perhaps with a subset of it, then X can 
comfortably use
> SPARQL for this task.  However, comparing a declarative (rule) 
> semantics with an
> algebraic (SPARQL) semantics is an apples and oranges comparison.  To be
> sure that SPARQL properly implements the rules, X would have to produce 
> the declarative semantics on her own.
> 
> A declarative semantics forms a bedrock on which to build a logic
> pyramid.  An algebraic semantics is essentially a dead-end.

Thanks for your comments. We're recording your feedback as a formal 
objection. To help us properly record and represent the objection, please 
let me know if there are any example queries that illustrate a difference 
in the declarative semantics you are looking for compared to the current 
semantics in the document.

> I wasn't recommending eliminating UNBOUND from the language; I was 
> recommending 
> relegating it to secondary status within the language, i.e., making it 
> a computed predicate and not according it a reserved word.  Its easily 
the
> most egregious hack in the language.

We'll also note this objection. I'm unclear as to whether you are 
objecting to the existence of the bound operator altogether, or to the 
potential combination of the bound operator and the logical-not operator. 
If you could clarify this, it would help me best represent your objection 
as the WG seeks advancement along the Rec. track.

many thanks,
Lee

> 
> thanks,
> Lee
> 
> Cheers, Bob
> 
> Bob MacGregor
> Chief Scientist
> Siderean Software, Inc.
> 310.647.5690
> bmacgregor@siderean.com
Received on Tuesday, 5 June 2007 18:18:13 GMT

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