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Re: ISSUE-148: RDF Concepts - IRIs do *not* always denote the same resource

From: Dan Brickley <danbri@google.com>
Date: Sat, 14 Dec 2013 16:53:28 +0000
Message-ID: <CAK-qy=4hXVF9Ce5t=YJEyB8tjvuEgt7mRWXgJWNLpMEH126X+A@mail.gmail.com>
To: Richard Cyganiak <richard@cyganiak.de>
Cc: public-rdf-comments Comments <public-rdf-comments@w3.org>, Guus Schreiber <guus.schreiber@vu.nl>, David Booth <david@dbooth.org>
file://dev/mouse isn't an artifact of interpretation semantics; nor the
platonic mouse of mouses...
On 13 Dec 2013 21:52, "Richard Cyganiak" <richard@cyganiak.de> wrote:

> Hi David,
> On 13 Dec 2013, at 19:23, David Booth <david@dbooth.org> wrote:
> > No, I cannot live with this.  The current draft of the RDF Concepts says:
> >
> >  "IRIs have global scope: Two different appearances of an
> >  IRI denote the same resource.
> >
> > and that is simply misleading and false, as explained here:
> >
> http://lists.w3.org/Archives/Public/public-rdf-comments/2013Dec/0073.html
> PLEASE, PLEASE, PLEASE don’t do this.
> It is true that an IRI can denote different things in different
> interpretations. But we are talking here about a brief and *informative*
> introduction to semantic web architecture of two pages. It cannot, and
> should not, get into the business of explaining interpretations and
> possible worlds.
> So we are concerned here with only one possible world, the one we live in.
> In this particular possible world, an IRI denotes the same thing wherever
> it occurs. For the vast majority of readers, this is all they ever need to
> know.
> Now, you are right, RDF Semantics introduces the notion of
> interpretations, and an IRI can denote different resources in different
> interpretations. But this denotation of different resources is not even a
> *feature*. It is simply part of the formalism that happens to be used to
> define what entailments are correct. Had the semantics been formally
> defined using inference rules rather than model theory, then the phrase you
> quote would be absolutely correct.
> In summary, David, you give us two alternatives.
> a) Either we need to introduce a brief informative account of the way IRIs
> work on the semantic web with caveats about multiple possible worlds.
> b) Or we can’t tell people that an IRI that occurs twice should always be
> taken as identifying the same thing.
> Either option is harmful to the intended audience of RDF Concepts. All in
> the name of being *technically* correct.
> Again, it’s a *non-normative* section, it’s the *introduction*, it’s
> intended to be understandable by people who will never look at RDF
> Semantics, and the sentence is even true within any given single
> interpretation!
> Best,
> Richard
Received on Saturday, 14 December 2013 16:54:02 UTC

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