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Re: statements about resources vs. representations

From: Pat Hayes <phayes@ihmc.us>
Date: Fri, 21 Nov 2008 18:05:02 -0600
Cc: "public-awwsw@w3.org" <public-awwsw@w3.org>
Message-Id: <BF25AD3C-6CB9-4013-AC20-1B1DECF2F49C@ihmc.us>
To: Jonathan Rees <jar@creativecommons.org>

On Nov 21, 2008, at 11:04 AM, Jonathan Rees wrote:

> On Nov 21, 2008, at 10:59 AM, Pat Hayes wrote:
>> On Nov 21, 2008, at 7:58 AM, Jonathan Rees wrote:
>>> (Using "representation" in the AWWW sense here.)
>>> Suppose I have a resource R, and for some reason I believe that
>>> R dc:creator author:Charles_Dickens.
>>> Now suppose that I do a GET to obtain a representation, and let F be
>>> the fixed resource (see [1]) whose representation is this  
>>> representation.
>>> (I'll need a term for the coercion of representation to fixed  
>>> resource, so
>>> I'll say "the FR of the representation.")
>>> Assuming good faith and proper functioning on everyone's part,
>>> can I conclude that F dc:creator author:Charles_Dickens . ?
>> Um... I must be missing something, because the answer to the  
>> question as posed is, "Obviously not", since no connection has been  
>> mentioned between R and F.  Did you intend them to have some kind  
>> of relationship, and if so, what kind? THe mental picture I  
>> currently have is that R is an actual copy of an old book, held in  
>> your hand, which you believe is authored by Dickens, while F is a  
>> web page somewhere that presumably has a URI which you used to do  
>> the GET.
>> Pat
> Sorry: I meant that I do a GET to obtain a representation *of R*.  
> That is, R has a URI U, and I do a GET on U, and the representation  
> (the representation that R will share with F) comes back as the  
> entity of a 200 response.

OK, but Im still puzzled. What *kind* of thing is R supposed to be?  
Take several cases.

(1) R is an actual book, a physical thing I found in a second-hand  
bookstore. My question for this case is, how did this R get to have a  
URI? And even if it did, how did you find out what that URI was? Put  
another way, what establishes the relationship between R and U?

(2) R is a Platonic abstract book, the kind of thing that can have an  
ISBN number; not a physical copy of the book but the 'edition' that  
said physical copy would be a copy of. This, plausibly, might have its  
own URI assigned by the publisher, say, which we can take U to be.  
Then F would presumably be, assuming a reasonably cooperative  
publisher (as opposed to a Dadaist who just wants to mess with your  
head), a webpage which was informative about the book or  edition of  
the book, whatever the ISBN number is supposed to individuate. Except  
that in this case, you would have been 303-redirected to this if http- 
range-14 is being followed, not had it delivered with a 200 code.

(3) R is F, in fact. This is the only possibility that is http- 
range-14 consistent with having its representation delivered with a  
200 code. But then I'm left wondering what it means when you say at  
the beginning that you "have" R. How does one "have" a Web resource,  
other than being the owner of it?  In which case how can you be so  
confused that you think Charles Dickens was the author of it (assuming  
of course that you aren't Charles Dickens yourself) ?

Any way, I can't make the various parts of your scenario all make  
intuitive sense at the same time.  What am I missing?

> If you mean that the class of old books and that of web pages should  
> be taken as distinct, and that R is a member of one and F is a  
> member of the other, that is an interesting position.

That would be my first option above.

> If you mean in addition that the two classes have no interesting  
> common superclass that could possibly be the domain of dc:creator

No, I wouldn't go so far as to claim that.  But just being in the  
domain doesn't imply that the property holds, which is what would be  
needed to carry the inference you mention.

> , that's very interesting - then my question of whether authorship  
> of a representation has to be compatible with authorship of a  
> resource that has that representation becomes unaskable, since only  
> one of these can meaningfully have an author.

Um.... authorship of a awww:representation? Do awww:representations  
HAVE authors? I thought they were created by software at the receiving  
end of an http GET transaction, and therefore don't have authors. I  
make Web pages, but the IHMC server makes awww:representations of  
them, and I have nothing to do with that. I don't even know when its  

> I'm trying to figure out whether there is any relationship between  
> the awww:representations of a resource and the resource, and if so  
> what it is.

Um... that one of them is an awww:representation of the other? What  
more do you need?

> It seems obvious that there is one - that it, it is possible to say  
> one thing about a resource that makes it impossible to say something  
> else about one of its representations, and vice versa.

If the resource is A, then the representation of it cannot be a  
representation of something that is not A. For any A. (? It can't be  
that easy, surely?)

> People look at representations to form theories about the resource,  
> and so on. I picked dc:creator because it seems like something that  
> is objective (potentially false, independently verifiable) and that  
> might be asserted on either thing in the wild by an RDF author not  
> prejudiced as we are.
> As usual, I like it when people take stands. Thanks for answering!

And to you  :-)

> -Jonathan

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Received on Saturday, 22 November 2008 00:06:19 UTC

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