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Re: [PROPOSAL] Named graphs in RDFa

From: Ivan Herman <ivan@w3.org>
Date: Thu, 20 Dec 2007 09:32:48 +0100
Message-ID: <476A28B0.9060401@w3.org>
To: "Hausenblas, Michael" <michael.hausenblas@joanneum.at>
CC: Mark Birbeck <mark.birbeck@x-port.net>, public-rdf-in-xhtml-tf@w3.org, SWD WG <public-swd-wg@w3.org>
Michael,

I am sorry, but I do not agree. Mark's explanation and 'theory' (as he
himself put it) is interesting, challenging, but we should not put this
into an official W3C Recommendation. As Mark said it very clearly, it is
a theory and it does not reflect any type of consensus...

Ivan

Hausenblas, Michael wrote:
> 
> Mark,
> 
> Thanks for your explanation - as always a pleasure to read.
> If I understood correctly this is basically what I was looking for! :)
> 
> I therefore withdraw my original proposal and would like to suggest
> that this aspect (or more precisely: your explanation of it ;)
> somehow finds its way into the RDFa Syntax document.
> 
> Cheers,
> 	Michael
> 
> ----------------------------------------------------------
>  Michael Hausenblas, MSc.
>  Institute of Information Systems & Information Management
>  JOANNEUM RESEARCH Forschungsgesellschaft mbH
>  Steyrergasse 17, A-8010 Graz, AUSTRIA
> ---------------------------------------------------------- 
> 
>> -----Original Message-----
>> From: Mark Birbeck [mailto:mark.birbeck@x-port.net] 
>> Sent: Wednesday, December 19, 2007 5:01 PM
>> To: Hausenblas, Michael
>> Cc: public-rdf-in-xhtml-tf@w3.org; SWD WG
>> Subject: Re: [PROPOSAL] Named graphs in RDFa
>>
>> Hi Michael,
>>
>> This is an interesting problem, and one I've avoided 
>> commenting on because it could take every waking minute of 
>> the day. :) Anyway, all of the following is in the 
>> 'theoretical' bin....
>>
>> I think RDFa is unusual in that it doesn't have a named graph 
>> problem in the way that, say, RDF/XML does, because the XHTML 
>> document *is* the 'named graph'.
>>
>> The interesting thing about an HTML/XHTML document is that 
>> there is both a head and a body section of the document, 
>> which means that we could define things in such a way that we 
>> are making *two* lots of statements; one lot about the 
>> document itself, and one lot about the 'content' referred to 
>> by the document.
>>
>> The document itself is a named graph, since it has a URL, and 
>> contains metadata. Of course, normally all metadata in the 
>> document is 'about'
>> that document unless overridden by an @about, so to 
>> distinguish between statements about the document (i.e., the 
>> graph) and statements about some other things you'd always 
>> have to add an @about.
>>
>> However, if a typical document looked like this:
>>
>>   <html>
>>     <head about="">
>>       ...statements about the named graph...
>>     </head>
>>     <body about="#">
>>       ...statements about the content, e.g., my FOAF page...
>>     </body>
>>   </html>
>>
>> you would effectively have a 'named graph', which is the 
>> information resource at "", accompanied by a resource, 
>> identified by "#"; note how this might also solve the 
>> interminable information resource question.
>>
>> (As it happens this trick of distinguishing between the 
>> document carrying the metadata and what the metadata is about 
>> could have been done with RDF/XML, but in RDF/XML if 
>> @rdf:about is empty it means that statements are being made 
>> about the current document; in short, there is no way to 
>> distinguish between the document that contains the graph, and 
>> the graph itself.
>>
>> If we also added a statement that the 'primary topic' of the 
>> named graph, was the resource identified in the body:
>>
>>   <html>
>>     <head about="">
>>       <link rel="foaf:primaryTopic" href="#" />
>>       ...statements about the named graph...
>>     </head>
>>     <body about="#">
>>       ...statements about the content, e.g., my FOAF page...
>>     </body>
>>   </html>
>>
>> then everything is complete; now, when someone links to the 'graph'
>> from an HTML page (the most likely scenario), it is a simple 
>> matter to sort out what exactly is being referred to.
>>
>> Regards,
>>
>> Mark
>>
>> On 19/12/2007, Hausenblas, Michael 
>> <michael.hausenblas@joanneum.at> wrote:
>>>
>>> All,
>>>
>>> Proposal:
>>> Add a mechanism to RDFa that allows to indicate a graph's 
>> provenance 
>>> (aka named graphs, etc.).
>>>
>>> In the first phase we should decide IF we want this (or not 
>> :), then 
>>> if/when we agree, we should discuss HOW to implement it.
>>>
>>> Rational:
>>> Due to the ongoing discussions [1] and Fabien's W3C member 
>> submission 
>>> [2] is ask myself:
>>> Why don't we introduce this feature in RDFa?
>>>
>>> As we are about (or partly already did) add new stuff 
>> anyway (such as 
>>> XHTML voc, CURIE, etc.), why not supporting this IMO very important 
>>> feature right from the beginning?
>>>
>>> Any thoughts?
>>>
>>> Cheers,
>>>         Michael
>>>
>>> [1] 
>> http://lists.w3.org/Archives/Public/semantic-web/2007Dec/0035.html
>>> [2] http://www.w3.org/Submission/rdfsource/
>>>
>>> ----------------------------------------------------------
>>>  Michael Hausenblas, MSc.
>>>  Institute of Information Systems & Information Management  
>> JOANNEUM 
>>> RESEARCH Forschungsgesellschaft mbH  Steyrergasse 17, A-8010 Graz, 
>>> AUSTRIA
>>>
>>>  <office>
>>>     phone: +43-316-876-1193 (fax:-1191)
>>>    e-mail: michael.hausenblas@joanneum.at
>>>       web: http://www.joanneum.at/iis/
>>>
>>>  <private>
>>>    mobile: +43-660-7621761
>>>       web: http://www.sw-app.org/
>>> ----------------------------------------------------------
>>>
>>>
>>
>> --
>>   Mark Birbeck, formsPlayer
>>
>>   mark.birbeck@formsPlayer.com | +44 (0) 20 7689 9232
>>   http://www.formsPlayer.com | http://internet-apps.blogspot.com
>>
>>   standards. innovation.
>>
> 

-- 

Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
PGP Key: http://www.ivan-herman.net/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf


Received on Thursday, 20 December 2007 08:32:59 GMT

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