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Re: Conneg representation equivalence

From: Richard Cyganiak <richard@cyganiak.de>
Date: Sat, 20 Mar 2010 16:58:56 +0000
Cc: Linked Data community <public-lod@w3.org>
Message-Id: <658C2786-D173-494F-8572-7E707626986A@cyganiak.de>
To: Vasiliy Faronov <vfaronov@gmail.com>
On 20 Mar 2010, at 15:32, Vasiliy Faronov wrote:
> I have a related question, about describing negotiated documents in  
> RDF.
>
> Suppose there's a web resource <http://example.org/> which has the
> following representations:
>
> - HTML in English, also available at <http://example.org/ 
> index.en.html>
> - HTML in Russian, also available at <http://example.org/ 
> index.ru.html>
>
> Let's say that one is a translation of the other.
>
> What can I say about <http://example.org/> in this scenario? Is it,  
> for
> example, a foaf:Document?

Yes.

> Can it have a dcterms:title? Can it have two dcterms:title's, one  
> with @en and one with @ru?

Yes and yes.

> Somehow it doesn't feel correct to me to say that this URI identifies
> one document.

Only if you apply an outdated, “offline” notion of the term  
“document”. Web documents are different from offline documents. Web  
documents change over time, while offline documents typically don't.  
Most importantly, web documents can have *multiple representations*,  
in multiple formats and languages, while we don't usually think about  
offline documents in that way.

(That's why the technical literature uses a different term,  
“information resource”, instead of the term “web document”. That term  
has its own problems though.)

> I may want to assert different things about them, e.g.
> text language, or link to the translator for the translated version.

You already have solved that problem by minting URIs for the  
individual representations. You can assert language, translator and so  
on for those URIs.

> But
> then, <http://example.org/> is the "canonical" URI for the resource,  
> the
> one that the outside world is mostly supposed to use, so it makes a  
> lot
> of sense to say *something* about it.

Anything that applies to all representations can be safely stated  
using the canonical URI. It also makes sense to relate the generic  
resource to the specific ones using hyperlinks or RDF statements.  
Inside the HTML representations, this is easily done. In RDF, there  
are several useful predicates in Dublin Core, e.g., dc:hasVersion and  
dc:hasFormat.

Best,
Richard




>
> Is there any best practice for this?
>
> -- 
> Vasiliy Faronov
>
>
Received on Saturday, 20 March 2010 16:59:31 UTC

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