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Re: Determination of subjects/objects (was: ISSUE-42)

From: Mark Birbeck <mark.birbeck@formsPlayer.com>
Date: Mon, 30 Jul 2007 18:18:34 +0100
Message-ID: <a707f8300707301018v1e579d43x82f8416f2b076f2@mail.gmail.com>
To: "Dan Brickley" <danbri@danbri.org>
Cc: "Knud Hinnerk Möller" <knud.moeller@deri.org>, "Manu Sporny" <msporny@digitalbazaar.com>, public-rdf-in-xhtml-tf@w3.org

Hi Dan/Knud,

The issue isn't bnodes, since we do have those in RDFa. The question
is whether to support 'named bnodes', which you get in RDF by using
@nodeID. (Early drafts of RDFa actually used to have a nodeID
attribute.)

I'm really interested to hear comments on the use-cases for this,
which will most likely come from those who use RDF a lot. The main
argument for its use in RDF more generally is to be able to have a
bnode that can be referenced from within a graph, but that cannot be
referenced outside that graph. In RDFa terms that would mean that you
have created a bnode that you want to be able to refer to in some
other part of the document, but you *don't* want anyone else in the
world to be able to make statements about it.

I can't think of any situations where I'd use that myself, but that
doesn't mean a thing. :)

Regards,

Mark

On 30/07/07, Dan Brickley <danbri@danbri.org> wrote:
>
> Knud Hinnerk Möller wrote:
> > Hi,
> >
> > Am 30.07.2007 um 17:15 schrieb Manu Sporny:
> >
> >> Mark Birbeck wrote:
> >>> I haven't had a chance to re-read this thread, so I'm not going to say
> >>> anything on the substance. But if you don't mind, I'd like to comment
> >>> on a recurring theme, which seems exemplified by the following:
> >>>
> >>>> 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.
> >>>>
> >>> I don't see the need to 'protect' authors who are not familiar with
> >>> RDF from RDF constructs that they will never use. If someone from the
> >>> RDF community thinks this is useful, and _if_ we can support it
> >>> without it getting in the way, then why not?
> >>
> >> Constructs such as "_:" are scary to non-RDF folks. :) From a
> >> historically RDF-unaware perspective (mine), I stared at the "_:"
> >> construct and had no idea what it does. It is not very intuitive.
> >>
> >> Even having seen it, I haven't taken the time to look up what it means.
> >> It will probably make sense when I do, but to somebody that is not
> >> trained in CS/EE/ECE/etc., this is a scary construct. To the lay web
> >> page author, it is syntactic gibberish.
> >>
> >> There is already a very strong feeling in the Microformats community
> >> that RDFa is far too complicated for most web page authors. The last
> >> thing most of them want to learn is yet another language syntax for
> >> describing what they see as "corner-cases of the language".
> >>
> >> I see your argument: If they aren't going to use it, and if it doesn't
> >> cause any harm, then why not put it in there?
> >>
> >> I would argue that you shouldn't put things in there that aren't
> >> absolutely necessary. It complicates the RDFa specification. If there is
> >> a need in the future, you can always add it in a later revision.
> >
> > I would really argue to have bnodes in RDFa: I know they are very
> > unpopular, and vocabularies like FOAF now recommend against using them.
>
> No they don't :) well, foaf in particular...
>
> I put a #me into the FOAF spec example, that's all.
>
> RDF is a language for representing and aggregating partial information
> into a greater whole. Sometimes that information lacks statements,
> sometimes those statements are missing well known identifiers. Sometimes
> the things the statements are about don't even have well known identifiers.
>
> There are things in FOAF such as isPrimaryTopicOf which are designed to
> help people live in such a world. But there is nothing FOAF or other RDF
> vocabs can do to get away from the basic fact: informational is not
> universally and evenly available. RDF authors do not have a godlike
> access to every fact and every identifier they might need. And so RDF
> data is inevitably a lossy, gappy thing. Sometimes missing statements,
> sometimes missing URIs. Because RDF is written by people, and people do
> not know everything. If they did, why would they bother exchanging RDF
> files with each other? :) And so we have bnodes.
>
> That said, "_:" in RDFa worries me too.
>
> Dan
>
>


-- 
  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 17:18:44 GMT

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