W3C home > Mailing lists > Public > semantic-web@w3.org > August 2007

Re: What if an URI also is a URL

From: Reto Bachmann-Gmür <rbg@talis.com>
Date: Mon, 27 Aug 2007 23:37:24 +0200
Message-ID: <46D34414.3030006@talis.com>
To: Oskar Welzl <lists@welzl.info>
CC: semantic-web@w3.org

Oskar Welzl wrote:
> Thank you for helping me on... the only point I don't get is:
>> Oskar Welzl wrote:
>>> c) Consequently, if I want to make a reference to my weblog (meaning the
>>> thing as such, a collection of all posts, pictures, the services offered
>>> etc.), I'd better not use http://oskar.twoday.net as this would only
>>> refer to one single HTML-document. In particular, the document served at
>>> http://oskar.twoday.net might have been dc:created yesterday, while the
>>> weblog as such started 2003.
>>> I'd have to make up something like http://oskar.twoday.net/id/thisblog
>>> and maybe state somewhere that http://oskar.twoday.net/id/thisblog has
>>> an indexDocument http://oskar.twoday.net 
>> I think there might be a confusion between the resource
>> <http://oskar.twoday.net/> and the representation returned by the
>> webserver. A Blog is an Information Resource which could be described as
>> an ordered collection of posts, the HTML returned by the webserver is
>> (or should be) a suitable representation of that thing. Depending on the
>> current time as well as the properties of the request the server may
>> deliver different representations of an invariable resource.
> So while I thought <http://oskar.twoday.net/> shouldnt be used to refer
> to the Blog as "the collection of posts", you seem to say now that the
> HTML-document returned by the server might well be taken as a suitable
> representation of it. Therefore (if I understand you correctly),
> <http://oskar.twoday.net/> *can* be used in RDF to refer to the thing
> known as "Oskars Blog" in the real world.
> Now isnt this a direct contradiction to the starting point, when TBL
> wrote:
>> The moment a server returns 200 OK for a request to the URI, it is  
>> saying it identifies a document.
> Identifiying a document is not the same as identifying a blog, even if
> the document is part of the blog. I can make statements about this one
> document that are not true for the blog and vice versa.
> Whats the point I'm missing? Or am I being fussy here again? ;)
This might have to do with the notion of "Document". For TimBL a
document is something more abstract than a sequence of bytes and a

On http://www.w3.org/DesignIssues/HTTP-URI.html TBL wrote:
> I want to make it clear that such things are generic (See Generic
> Resources) <http://www.w3.org/DesignIssues/Generic> -- while they are
> documents, they generally are abstractions which may have many
> different bit representations, as a function of, for example:
>     * Time -- the contents can vary with revision --
>     * Content-type in which the bits are encoded
>     * Natural language in which a human-readable document is written
>     * Machine language in which a machine-processable document is written
>     * and a few more
I guess that using the term "Informartion Resource" rather than
"document" is less prone to misunderstandings.


Reto Bachmann-Gmür
Talis Information Limited

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Received on Monday, 27 August 2007 21:37:31 UTC

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