RE: statements about resources vs. representations

> From: Pat Hayes
>
> On Nov 21, 2008, at 2:17 PM, Jonathan Rees wrote:
>
> > On Nov 21, 2008, at 1:39 PM, Harry Halpin wrote:
> >
> >> Alan Ruttenberg wrote:
> >>> AFAIK there is no way to make a statement about a representation,
> >>> only about a resource. [ . . . ]
> >
> > But AWWW and RFC 2616 talk about representations, and we do too.
> > We have to in order to talk about the semantics of HTTP.
> > Just because some people don't want to talk about them doesn't mean
> > such talk should be prohibited - that would be unscientific and
> > undemocratic.
> >
> > And of course they're exceedingly important. If all representations
> > were to disappear from the earth, the Web would cease to exist. So
> > it seems not only permissible, but important to talk about them.
>
> Hold up. I think what Harry should have said is that they are too
> ephemeral for someone to want to give them an enduring name or
> identifier. But there are other ways to refer to things than baptizing
> them with a URI for all time. For example, one might refer to a
> representation by specifying the resource that emitted it (which has a
> URI, by assumption) and the exact time it was created (a literal),
> and the "name" of the resource would then be a good old RDF blank node. No
> URI involved, but you can still talk about it.

Well put, except that there is one more parameter required: the information contained in the HTTP request, since the representation may depend not only on time, but on anything contained in the request.  That's why I suggest thinking of an information resource f as a function:

  f: (Time x Request) --> Representation




David Booth, Ph.D.
HP Software
+1 617 629 8881 office  |  dbooth@hp.com
http://www.hp.com/go/software

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Received on Friday, 21 November 2008 23:01:17 UTC