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Re: Media types and assertions

From: Mark Baker <distobj@acm.org>
Date: Thu, 11 Mar 2004 15:21:39 -0500
To: Pat Hayes <phayes@ihmc.us>
Cc: www-rdf-comments@w3.org
Message-ID: <20040311152139.P2194@www.markbaker.ca>

Hi Pat,

On Thu, Mar 11, 2004 at 11:07:11AM -0600, Pat Hayes wrote:
> The resignation you speak of is real, and represents a kind of blurry 
> emerging early social consensus that deployed RDF is usually being 
> used to assert things, mostly.

Ok, thanks.

> Right now, we can muddle along without 
> needing to 'solve' this problem, which I think is the best thing to 
> do until the issues become clearer and we all get more experience 
> with deployed RDF/OWL applications.

I'm not so sure.  I'm not certain there'll be problems

> >I think this is pretty important, and more important than getting the
> >registration out (since people are using it, and I haven't observed any
> >interop problems with it
> 
> Just wait. There will be.

Perhaps.  But I expect that would only be a result of the ambiguity I
believe to currently be in the draft.  Which brings us to ...

> >).  Ambiguity in media types is not a nice
> >thing.
> 
> There is no ambiguity.  The media type identifies the XML as being 
> RDF, which determines how it is to be semantically interpreted and 
> enables engines to handle it appropriately (parse it, draw valid 
> conclusions from it, check it for consistency, etc. - all determined 
> by the specs as they stand). This seems entirely appropriate for a 
> media type: its like identifying HTML as being HTML. The content of 
> some RDF - the proposition it expresses - is the same whether it is 
> being asserted or not, and it is this content that the semantics in 
> the spec determines.
>
> Media type hasnt got anything to do with social contracts between 
> sender and receiver. I can use HTML as wallpaper, and it is still 
> HTML; similarly with RDF.  Whether it is being asserted or denied or 
> quoted or whatever is another set of issues altogether, which has 
> more to do with how people behave than with what RDF means.

Sorry, but I disagree quite strongly.

If somebody on the Web can't distinguish between an RDF message which
says "Mark hates bananas" versus one that says "Mark hates bananas (but
not really)" (aka unasserted), then there is a failure to communicate.
The "but not really" part must be part of the message.  It can either be
done through mechanisms in the RDF specs themselves (e.g.
parseType="literal"), or it can be done in an encapsulating spec or
registry, such as the media type registration.

Mark.
-- 
Mark Baker.   Ottawa, Ontario, CANADA.        http://www.markbaker.ca
Received on Thursday, 11 March 2004 15:20:06 UTC

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