- From: Andy Seaborne <andy.seaborne@epimorphics.com>
- Date: Fri, 15 Feb 2013 19:38:42 +0000
- To: RDF-WG <public-rdf-wg@w3.org>
On 15/02/13 16:59, Pat Hayes wrote:
> But let me ask you about this example. You are assuming here that the
> _:doc1 in the triple in the default graph, and the _:doc1 used as a
> graph label, refer to the same thing, which is the moon-green-cheese
> graph, right? What is interesting here is that this assumption seems
> inevitable when we have a bnode involved, as here, but (the WG has
> decided) it cannot be assumed when an IRI is used. So this data:
>
> {ex:doc1 :author "Bob" }
> ex:doc1 {:TheMoon :madeOf :greenCheese }
>
> does *not* entail that Bob is the author of the graph (since
> 'ex:doc1' might denote something else, which is what the default
> graph would be about, and not about the graph.) So this actually
> gives us a new, Manu-independent, reason to allow bnodes as graph
> labels in datasets: they provide exactly the missing expressivity
> that is needed to have the default graph act as genuine metadata.
I don't understand this bit - why do bNodes force a specific
relationship between graph label and graph in a way that URIs don't?
If ex:docs is the "location has state" relationship of URI to graph,
surely _:x can have that relationship.
One simple entailment design would be:
{ex:doc1 :author "Bob" }
ex:doc1 {:TheMoon :madeOf :greenCheese }
=>
{_:x :author "Bob" }
_:x {:TheMoon :madeOf :greenCheese }
Andy
Received on Friday, 15 February 2013 19:39:22 UTC