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RE: on documents and terms [was: RE: [WNET] new proposal WN URIs and related issues]

From: Booth, David (HP Software - Boston) <dbooth@hp.com>
Date: Sat, 29 Apr 2006 00:00:56 -0400
Message-ID: <EBBD956B8A9002479B0C9CE9FE14A6C20B9322@tayexc19.americas.cpqcorp.net>
To: "Pat Hayes" <phayes@ihmc.us>, "Frank Manola" <fmanola@acm.org>
Cc: <public-swbp-wg@w3.org>

> From: Pat Hayes [mailto:phayes@ihmc.us]:
> >Booth, David (HP Software - Boston) wrote:
> >>>From: Frank Manola:
> . . .
> >>>1.  An "HTTP endpoint", which is a
> >>>computational process running on hardware, 
> >>>which processes the GET request and emits http 
> >>>codes and bit-strings.
> >>
> >>Yes.  This is the "information resource", defined in an operational 
> >>style.
> >>
> >>Side note: I actually used the term "logical
> >>HTTP endpoint", not just "HTTP endpoint", 
> >>because an "information resource" is associated 
> >>with an entire URL minus the fragment 
> >>identifier, whereas a Web server is (normally?) 
> >>associated with only the domain+server part 
> >>(ignoring the path and query string parts). 
> >>For example, given the URI 
> >>http://example.org/foo?bar#fum , 
> >>http://example.org/ , http://example.org/foo 
> >>and http://example.og?bar may all correspond to 
> >>different "information resources", even though 
> >>they would be served by the same Web server 
> >>associated with example.org.
> > . . .
> We are now distinguishing between an endpoint and 
> an implementation of an endpoint?? This is 
> getting out of hand. So the running code is an 
> implementation of a logical endpoint which is the 
> real information resource. 

Correct. 

> Presumably I could 
> implement the same logical endpoint somewhere 
> else on the network, right? (If not, where is the 
> utility in distinguishing them?) Would its URI 
> still identify it - the logical endpoint - at 
> that other place on the network? Or would it in 
> fact identify the implementation? Etc. ..

Great question!  Yes, the old URI would still identify it, and the new
URI would also identify it.  The new URI would be a URI alias[10].

> . . .
> >Also, it seems to me this is very much bound up
> >with the distinction being made between 
> >information resources and other resources.  This 
> >distinction, and the different server return 
> >codes being associated with it, seem to create a 
> >binary (yes/no) answer to the question, "does 
> >the representation that has been returned convey 
> >all of the essential characteristics of the 
> >resource denoted by the URI you've dereferenced" 
> >(in the opinion of the person setting up the 
> >relationship between the URI and the 
> >representation that gets returned).  Clearly 
> >there's not a whole lot of room for nuance here 
> >(!), but there does seem to be at least some 
> >kind of semantic relationship.
> 
> Well, no, I think that this virtually rules out 
> any kind of semantic relationship, since I know 
> of no way to analyze 'represents' semantically 
> which would provide for ALL the essential 
> characteristics of the represented to be captured 
> by the representation. (It depends, of course, on 
> what one means by the weasel words, in this case 
> "essential".) Certainly a description cannot do 
> this, except in cases not of wide interest (in 
> mathematics, for example, where notions like 
> 'abelian group' are defined so that they can be 
> fully characterized by finite descriptions; 
> notice that they have to be Platonic ideals in 
> order for this to be possible.) 

Hold on.  It sounds like you are now talking about "resources" in
general, rather than only "information resources".  In the WebArch, the
phrase about "all of their essential characteristics can be conveyed in
a message" is only talking about "information resources".  A piece of
information *is* a Platonic ideal and *can* be losslessly copied.

Nonetheless, as I explained in my reply to DanC[13], it seems to me that
the TAG's notion of an "information resource" is necessarily more
abstract than merely something (such a piece of information) whose
"essential characteristics can be conveyed in a message", even though
the WebArch[10] doesn't say so.

[1] DBooth proposed definition of "information resource":
http://lists.w3.org/Archives/Public/public-swbp-wg/2006Apr/0053.html

[10] WebArch definition of "information resource":
http://www.w3.org/TR/2004/REC-webarch-20041215/#def-information-resource

[13] DBooth reply to DanC:
http://lists.w3.org/Archives/Public/public-swbp-wg/2006Apr/0103.html

David Booth
Received on Saturday, 29 April 2006 04:02:49 UTC

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