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Re: Playing with the model

From: Libby Miller <Libby.Miller@bristol.ac.uk>
Date: Thu, 28 Feb 2002 21:51:57 +0000 (GMT)
To: "Sean B. Palmer" <sean@mysterylights.com>
cc: w3c-wai-er-ig <w3c-wai-er-ig@w3.org>, Wendy A Chisholm <wendy@w3.org>, Libby Miller <Libby.Miller@bristol.ac.uk>, danbri <danbri@w3.org>
Message-ID: <Pine.GSO.4.44.0202282151050.29186-100000@mail.ilrt.bris.ac.uk>

sorry if I misled anyone, I just glanced at it, been rather busy and
tired today. I hope to spend some time looking at earl with wendy
tomorrow.

sorry for any confusion...

Libby

On Thu, 28 Feb 2002, Sean B. Palmer wrote:

> > Sean and Danbri, Libby said this was "implicit reification."
>
> This doesn't seem to be "fake" or "implicit" refification going by
> Libby's description of it in her "RDF Annotations" paper [1]. In that
> model, things are grouped under bNodes and given properties. With this
> model, things are just asserted in the model with no grouping or way
> of preserving the context information.
>
> > What are the implications on queries?
>
> The implication is that you either can't have two different
> evaluations in one document, or you can't query it at all. I'm not
> sure how this would fit into the reification by hypertext idea [some
> notes on that a bit further down].
>
> Consider the following problem (which I've already outlined twice at
> [2] and [3], but here it is again). You may have one document which
> contains:-
>
>    :Sean earl:asserts <http://example.org/> .
>    <http://example.org/> earl:passes :WCAGA .
>
> and then in another document you have:-
>
>    :Wendy earl:asserts <http://example.org/> .
>    <http://example.org/> earl:fails :WCAGA .
>
> notwithstanding the fact that asserting a bit of WebContent doesn't
> make much sense (and could be misconstrued as asserting the semantics
> of the WebContent, which is certainly *not* what we want!), when you
> merge the RDF documents you get a contradiction:-
>
>    :Sean earl:asserts <http://example.org/> .
>    :Wendy earl:asserts <http://example.org/> .
>    <http://example.org/> a earl:WebContent;
>       earl:passes :WCAGA; earl:fails :WCAGA .
>
> It's impossible to query it usefully. Who said that it passes, and who
> said that it fails?
>
> And then there's reification by hypertext, treating the two documents
> as things that we don't necessarily believe. The problem with that is
> that XML RDF has no way to quote a set of statements other than using
> log:quote as a parse type. It also has no way to identify the root
> context of the document, unless you make a link from the document to
> it's semantics using log:semantics or something.
>
> Of course, the other big problem with that is that you can't have lots
> of different evaluations (i.e. with different assertors) in one
> document. We discussed that months ago, and the people on the call
> (Jim and Nick, IIRC) didn't think it was a good idea.
>
> [1] http://ilrt.org/discovery/2001/04/annotations/#fake
> [2] http://lists.w3.org/Archives/Public/w3c-wai-er-ig/2002Feb/0053
> [3] http://lists.w3.org/Archives/Public/w3c-wai-er-ig/2002Feb/0056
>
> --
> Kindest Regards,
> Sean B. Palmer
> @prefix : <http://purl.org/net/swn#> .
> :Sean :homepage <http://purl.org/net/sbp/> .
>
>
Received on Thursday, 28 February 2002 16:54:35 GMT

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