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Re: Determination of subjects/objects

From: Mark Birbeck <mark.birbeck@formsPlayer.com>
Date: Fri, 27 Jul 2007 17:24:23 +0100
Message-ID: <a707f8300707270924t4741f94epb90a7d85c51c2bfc@mail.gmail.com>
To: "Ivan Herman" <ivan@w3.org>
Cc: "Ben Adida" <ben@adida.net>, public-rdf-in-xhtml-tf@w3.org

Ivan,

I'm not sure that the 'RDF identity' is a useful term. I can see why
Ben introduced it, to help formulate the rules summary, but I'm not
sure it does actually help.

Another way to look at what is being done is that the 'context' for
contained statements is being set; we could say that the context is
set by the value of @href, or @resource, or some bnode, or whatever.

Regards,

Mark

On 27/07/07, Ivan Herman <ivan@w3.org> wrote:
>
>
> Ben Adida wrote:
> >> [ a rdf:Seq;
> >>      rdf:_1 <#A>;
> >>      rdf:_2 <#B>.
> >> ]
> >> <#A> p:q "bla2".
> >> <#B> p:q "bla2".
> >>
> >> Note that, as a side effect of the Ben rules, there is _no_ difference
> >> between @about and @href in this setting...
> >
> > Okay, *this* is a problem, I think. I know the way I worded "the rules",
> > it appears that @about is then the RDF identity, so it appears that it
> > can be the object when you write:
> >
> >    <li rel="rdf:_1" about="#A">
> >
> > but I think that is very wrong. Because, if you add @resource, then
> > @about suddenly becomes the subject. And that's quite confusing.
> >
> > It leads me to wonder if the rules are a bit wrong or inconsistent.
> >
> > If you were to write resource="#A", then I would agree, but as it
> > stands, it bothers me. And, in fact, this is the Achille's heel of this
> >  "syntactic sugar for collections" issue: if you add other RDFa
> > attributes, you screw up the resulting output.
> >
>
> Ben, I remember I was surprised when realizing that, too. But, just to
> really separate the issues, I do not believe this has anything to do
> with the collection issue. The very same happens with
>
> <span rel="a:b" about="#b">asasfas</span>
>
> You rules in
>
> http://www.w3.org/mid/46A8D3ED.2080404@adida.net
>
> say:
>
> - - @rel (conversely @rev) creates triples with the given predicate. The
> object of @rel (conversely the subject of @rev) is the "RDF identity" of
> the current element...
>
> - the RDF identity of an HTML element is, in order of precedence
>         - @resource
>         - @href
>         - @src if it's an IMG
>         - @about
>         - a new bnode
>
> meaning that we would get
>
> <> a:b #b.
>
> for the element above and if we added a @href then suddenly the @about
> becomes the subject of a:b.
>
> I am not saying this is not confusing, I am just saying that this is
> _not_ related to the collection syntactic sugar. Ie, I still believe the
> collection issue is, essentially, closed (I can use @resource in all my
> examples, eg, as resource="_:", without problems).
>
> I am not sure what to do with that stuff. I have to run now, maybe you
> may want to look at the different cases with the @about removed from the
> RDFI calculation.
>
>
>
> [snip]
> >
> > I have a visceral problem with about="_:", and that is that it makes
> > bnodes explicit, which I really don't want to do to HTML authors. That's
> > just too much RDF.
> >
> > We may begin to hit diminishing ROI here, and I'm starting to lean
> > towards supporting fewer of these constructs in order to not complicate
> > the syntax. I can't see myself being convinced that about="_:" is going
> > to help without hurting more....
> >
>
> I do believe that (1) "_:" will be very rarely used and for RDF people
> only but (2) in some edge cases it is difficult to avoid it. Any other
> syntactic solution would lead to real complications I believe, and I
> also believe that getting a sequence of anonymous and untyped bnodes is
> sometimes necessary...
>
> Ivan
>
>
>
> > -Ben
> >
>
> --
>
> Ivan Herman, W3C Semantic Web Activity Lead
> Home: http://www.w3.org/People/Ivan/
> PGP Key: http://www.ivan-herman.net/pgpkey.html
> FOAF: http://www.ivan-herman.net/foaf.rdf
>
>


-- 
  Mark Birbeck, formsPlayer

  mark.birbeck@formsPlayer.com | +44 (0) 20 7689 9232
  http://www.formsPlayer.com | http://internet-apps.blogspot.com

  standards. innovation.
Received on Monday, 30 July 2007 12:41:18 GMT

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