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Re: [pedantic-web] Re: The OWL Ontology URI

From: Dan Connolly <connolly@w3.org>
Date: Thu, 13 May 2010 11:48:35 -0500
To: Pat Hayes <phayes@ihmc.us>
Cc: Jonathan Rees <jar@creativecommons.org>, AWWSW TF <public-awwsw@w3.org>
Message-ID: <1273769315.3925.4531.camel@pav>
On Thu, 2010-05-13 at 10:53 -0500, Pat Hayes wrote:
> On May 13, 2010, at 10:18 AM, Dan Connolly wrote:
> > On Thu, 2010-05-13 at 00:03 -0500, Pat Hayes wrote:
> >> Dan, I don't think I've got my point across, and its getting lost in
> >> all this confusion about information resourceness. Its really a very
> >> simple point, and I can make it with a very simple example.   
> >> Suppose A
> >> is an RDF graph, and B is an RDF/XML file which encodes/is a surface
> >> syntax of/represents (choose your favorite terminology) that graph A.
> >> And suppose U is a URI which "identifies" B, in the sense that what
> >> you get back, when you do an HTTP GET using U, is a
> >> 'representation' (in the REST sense) of B with a 200 code attached.
> >> That is, the relationship between U and B is exactly like that  
> >> between
> >> the URI of a web page, and the web page itself.
> >
> > That's perhaps a different architecture; i.e. a different way of  
> > looking
> > at things than is in webarch and REST.
> >
> > A typical web page has various representations over time, and
> > when we link to the web page, we don't link to any one of them,
> > but to all of them (indexed by time). So (in webarch/REST) U
> > isn't a URI for B, but for something that B represents.
> Yes, I know. But lets take a very very simple case, to make the point,  
> where the resource does NOT change over time. Many  Web resources are  
> like this; and the point being discussed here doesn't seem to depend  
> on B being dynamic in this way.

OK, but even in the case where the resource is not dynamic, U
is a URI for the resource, not for the representation.

>   (Although, if it is part of the  
> nature of a REST-identifiable resource that it is dynamic, then that  
> is even more reason why an RDF graph - a mathematical set - can't be  
> one of them.)

No... as far as I'm aware, a constant function is fine.

> > Again, please take a look at the figure in the webarch intro
> >  http://www.w3.org/TR/webarch/#intro
> >
> > There we see that http://weather.example.com/oaxaca identifies
> > a weather report (a web page) which is represented by
> > an HTML document.
> And when that document was first drafted, I asked, what exactly IS  
> this thing called a 'weather report'? And the only answers I got  
> (other than being told not to ask such questions) were along the lines  
> of it being a computational entity which emits XHTML when prodded by a  
> GET, ie a Web page. I know in REST it is, formally, a function from  
> times to representations (of it), which is mathematically correct but  
> wholly uninformative as to what kind of thing it is, as it can be  
> applied to any function from times to anything.

Indeed, REST doesn't constrain what resources are.

> >> My point is simply that under these circumstances, we are pretty much
> >> obliged by http-range-14, as I understand it, to say that U denotes  
> >> B;
> >> that is, it denotes the thing it HTTP-identifies.
> >
> > You keep saying that, and I keep asking how you come to that
> > conclusion. I thought perhaps using more formal terms and going
> > slower would help, but evidently not. Oh well.
> If this understanding of http-range-14 is wrong, then please tell me  
> exactly how, and what I should understand it to mean. But please do so  
> without using the term "information resource".

Umm... I don't see how that's possible. The only content of the
httpRange-14 decision is that resources with representations
(i.e. that give 200 responses) are information resources
(whatever that means). Literally:

   a) If an "http" resource responds to a GET request with a
      2xx response, then the resource identified by that URI
      is an information resource;

   -- http://lists.w3.org/Archives/Public/www-tag/2005Jun/0039.html

It's not a very interesting result at all; it's pretty clearly
a paper consensus (i.e. a decision that just papers over
the substance of the issue). I think I abstained. Ugh...
no, I ran out of energy to even do that.

You seem to read much more into it than is there.

It in no way licenses an inference from
  U denotes R and R is represented by B
  U denotes B.

Dan Connolly, W3C http://www.w3.org/People/Connolly/
gpg D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Thursday, 13 May 2010 16:48:19 UTC

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