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Re: Turtle data-type

From: Peter Ansell <ansell.peter@gmail.com>
Date: Wed, 29 May 2013 15:38:31 +1000
Message-ID: <CAGYFOCQM-zp+A2n3bo0gfVmaEVnq5H=RvFjjsHCa3LVZ3nJ7NA@mail.gmail.com>
To: Henry Story <henry.story@bblfish.net>
Cc: Kingsley Idehen <kidehen@openlinksw.com>, public-rdf-comments@w3.org
On 29 May 2013 15:29, Henry Story <henry.story@bblfish.net> wrote:

>
> 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.
>
>
IMO, Laura Lane *would* believe that Clark Kent is a Hero if she were
privileged to know the information inside of *either* the quotation or the
reification.

Are you trying to create an alternative for reification for use in RDF that
is specifically not compatible with OWL to avoid conflicts with the OWL
semantics?


> 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.
>
>
So if there are no new semantics, does that imply that the quotation has no
effect unless the interpreter manually extracts the Turtle from the Literal
and interprets it outside of the RDF graph derived from the document?

Are you able to use the existing well-known W3C URL for Turtle,
http://www.w3.org/ns/formats/Turtle , and others from the list at
http://www.w3.org/ns/formats/ in a similar way?

Peter
Received on Wednesday, 29 May 2013 05:39:01 UTC

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