W3C home > Mailing lists > Public > public-rdf-wg@w3.org > April 2011

Re: ISSUE-30: How does SPARQL's notion of RDF dataset relate our notion of multiple graphs?

From: Dan Brickley <danbri@danbri.org>
Date: Sun, 17 Apr 2011 10:07:00 +0200
Message-ID: <BANLkTi=JooVxu5bNzSYcAAgRPBC9nJ5z2A@mail.gmail.com>
To: Richard Cyganiak <richard@cyganiak.de>
Cc: Pat Hayes <phayes@ihmc.us>, Ivan Herman <ivan@w3.org>, RDF Working Group WG <public-rdf-wg@w3.org>
On 17 April 2011 00:53, Richard Cyganiak <richard@cyganiak.de> wrote:
> Pat,
>
> On 16 Apr 2011, at 22:50, Pat Hayes wrote:
>>> This part of SPARQL is successful and useful despite being disconnected from the RDF Model Theory. RDF Datasets as they are defined in SPARQL have no impact on entailments, and therefore do not require a relation to the RDF Model Theory.
>>
>> The model theory is the semantics of RDF.
>
> Yes, that's what it says on top of the document.
>
>> It bears on any operation on RDF that is sensitive to the meanings of URIs or triples or literals. It is not purely concerned with entailments.
>
> What operations, beside inference, are you talking about?
>
> My understanding is that the RDF Model Theory exists to define which inferences are valid, given an RDF graph. What other purpose does it serve?

It helps us understand the kinds of transformations on RDF graph data
that are truth-preserving, also the kinds that change the meaning of
the graph such that the derrived graph says something different about
the world. You can think of those in terms of entailments I guess; the
mistake is to think 'I'm not writing a rule engine, so I can ignore
that mathsy spec".

Dan


>> The RDF model theory is normative. It is not something that can be handily ignored just because someone does not like it.
>
> *Reality* is normative. It is not something that can be handily ignored just because someone doesn't like it. The RDF model theory, on the other hand, *is* being ignored by most if not all recent successful RDF-based technologies. This does not appear to be to their detriment.

Technologies don't ignore things - perhaps you mean technologists?
Received on Sunday, 17 April 2011 08:07:28 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:25:41 GMT