W3C home > Mailing lists > Public > www-tag@w3.org > May 2005

Re: making progress on httpRange-14 -- yet another suggestion

From: Harry Halpin <hhalpin@ibiblio.org>
Date: Fri, 6 May 2005 20:19:48 -0400 (EDT)
To: "Roy T.Fielding" <fielding@gbiv.com>
Cc: W3C TAG <www-tag@w3.org>
Message-ID: <Pine.LNX.4.61.0505062007090.5624@tribal.metalab.unc.edu>

 	While I might add I agree with much of the substance of your 
point, that was a minor aside :) and I think you missed my point as well.

First, yes - information resources can be ambiguous on some level.
I think many people would argue that they are representations encoded
as bits (information resources) are *less ambiguous* than URIs that
I belive represent Tim Bray, but when I go to that URI I get either
his blog or a 404 error. If I want to share the information resource, then 
I just tell my friend the URI, and if he has any questions about it, he 
HTTP GETs a representation of it. The question I believe is what to do 
when there's no obvious representation of the resource at hand.

The key sentence you said is that:
> on the Web.  Those people are wrong -- there are millions of
> abstractions represented on the Web right now and they aren't
> going to go away just to make it easier for computers to do AI.
That's the point: these *abstractions* are being *represented*. The 
question is not *are* they being represented, the question is *how*.

Right now there are virtually little to no guidelines in this area.
If I have a SemWeb ontology and I want to refer to "Tim Bray" qua person,
I can pick a http:// URI and just do make my statements about that URI.
However, should I take his photo and put it at that URI? Leave that URI
empty and get a 404 error? Or should I using content-negotiation serve
RDF? Or should I just point that URI to his blog? And how does someone
or a machinebesides me, perhaps someone with less statements about that 
URI in RDF,  know what the heck that URI means? This are not insufficient 
solutions, but actual questions the TAG could answer.

Getting to the heart of this would allow people to do *exactly* what
you describe:
> My personal favorite is to make the relations specific about
> whether they refer to the resource or a set of representations,
> which is something that can be done in a definitional sense
> without changing any of the technology [though it would help a
> great deal if the technology supported temporally-qualified
> assertions]. That way, people and machines don't need to
> create ambiguous assertions in the first place.

That is what some people are advocating, and only some are 
advocating changing a URI scheme or adding hashes. Personally, my
favorite is to settle for a standard XHTML human readable representation 
(ala RDDL) for the non-information resource, and then use content 
negotiation to serve RDF/XML. This not only makes the relations specific, 
but does so in a human and machine-readable manner. I don't see how
this breaks http, and perhaps you could convice me that this does.

Received on Saturday, 7 May 2005 00:19:53 UTC

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