Print

Print


On 07/10/2014 11:38 AM, Robert Sanderson wrote:
>
> Hi Stuart,
>
>
>
> On Wed, Jul 9, 2014 at 4:28 PM, Stuart Yeates <[log in to unmask]
> <mailto:[log in to unmask]>> wrote:
>
>     On 07/10/2014 11:15 AM, Robert Sanderson wrote:
>
>         Thus:
>             _:bnode1 a bf:Instance ;
>                bf:uri _:bnode2 .
>             _:bnode2 a bf:Identifier ;
>                bf:identifierValue "http://www.example.com/books/__book1
>         <http://www.example.com/books/book1>" .
>
>         The first reads as: "There is a resource without an identifier, an
>         Instance, and it has an identifier that's a URI."
>
>
>     The first should read "There is a resource (which I'm not supplying
>     an global identifier for right here), an Instance, and it has an
>     identifier that's a URI."
>
>     "_:bnode1" is an identifier, it's just a scoped identifier (limited
>     to the current dataset / file). Think of it as like a file:/// or a
>     http://localhost/ URI; very useful for internal processes and
>     processing, but not to be shown in public.
>
>
> Yes, I was careless with the use of "identifier" :)  I did indeed mean
> without a global identifier.
>
> http://www.w3.org/TR/rdf11-concepts/#section-blank-nodes is clear that
> blank nodes are disjoint from IRIs, and are always locally scoped.  If
> it wasn't an identifier /at all/ you couldn't refer to it in the graph.
>
> However I don't think that changes my point that it's very strange to
> say, as corrected:
>
> Line 1: There is a resource without a global identifier which is an
> Instance.

The implication of using a blank node is not "without a global 
identifier" but "without a global identifier I care to supply here".

There are lots of reasons where graphs are likely to use blank nodes 
rather than global identifiers for many or most of their references to a 
thing.

cheers
stuart