W3C home > Mailing lists > Public > public-rdf-comments@w3.org > May 2013

Re: Turtle data-type

From: Henry Story <henry.story@bblfish.net>
Date: Wed, 29 May 2013 07:29:12 +0200
Cc: public-rdf-comments@w3.org
Message-Id: <E498EBCF-6903-476C-8011-022586A3BA4C@bblfish.net>
To: Kingsley Idehen <kidehen@openlinksw.com>

On 28 May 2013, at 21:41, Kingsley Idehen <kidehen@openlinksw.com> wrote:

> On 5/20/13 11:39 AM, Henry Story wrote:
>> In Turtle there is no way of specifying a graph (other than through reificiation which
>> is understood to be broken).
> 
> Why is reification assumed to be broken? I think the perception is that its cumbersome due to data bloat. Like blank nodes, this is a feature of RDF that's often misunderstood and then in the process maligned.
> 
> Reification is the powerful mechanism for granular descriptions of triples (statements) without exiting existing RDF semantics.

It does not do quotation the way we need it.

I want to express the following:

Laura Lane believes that Superman is a Hero .
Superman is Clark Kent .

With the suggested notation .

lane:Laura believes """@prefix ...
   super:man a Hero .
"""^^lang:Turtle .
super:man owl:sameAs kent:Clark .

With reification

lane:Laura believes _:b .
_:b rdf:subject super:man ;
    rdf:relation rdf:type ;
    rdf:object Hero .
super:man owl:sameAs kent:Clark .

Now since owl:sameAs allows substitution of identicals salva veritate,
it follows from the reification example but not from the quotation example
that Laura Lane believes that Clark Kent is a Hero.

You can argue that is not broken because it is not the same as quotation
and it just does something else, and that would be fine. 

But we need the quotation mechanism, for many use case. It is not bringing any new
semantics into RDF in any case: it's just asking for a notation to 
express what you can already express. We'd just like a standard notation
for something as important as this. defining lang:Turtle as a datatype,
with a well known w3c url.



> -- 
> 
> Regards,
> 
> Kingsley Idehen	
> Founder & CEO
> OpenLink Software
> Company Web: http://www.openlinksw.com
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> LinkedIn Profile: http://www.linkedin.com/in/kidehen
> 
> 
> 
> 
> 

Social Web Architect
http://bblfish.net/
Received on Wednesday, 29 May 2013 05:29:44 UTC

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