- 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