On Thu, Nov 28, 2013 at 1:23 AM, Milorad Tosic <[email protected]> wrote:
> It looks like that you are trying to address the skolemization problem [1]?
> Blank nodes are considered 'something that not exist' when it comes to URIs
> and resources. They are simply wrappers for resources and not resources on
> their own. So, something that doesn't exists can not have materialized
> context. Of course, there are several approaches based on skolemized blank
> nodes, but problems similar to your problem in hand must be solved there also
> with some other consequences.
I don't think it's right to say that they're "wrappers for resources
and not resources on their own". A blank node is still a node, it's
just not a literal or a URI node. I realize that the documentation
does talk about blank nodes as serving as existential variables.
E.g.,
[ :name "John Doe" ]
could be treated as the logical formula
exists x . ( x :name "John Doe" )
but in practice, blank nodes are often used in a way more like
anonymous (and distinct) objects. We see this in that while two
logical formulae of the form "exists x . x :name "John Doe"" and
"exists x . :name "Jane Doe" would allow the the _witnesses_ to those
formulae to the be the same (i.e., there's a single individual with
both names), people writing
[ :name "John Doe" ]
[ :name "Jane Doe" ]
don't typically expect that there might just be _one_ thing that has both names.
The task here, then, is to map blank nodes that appear in the data to
IRIs because another system requires them.
--
Joshua Taylor, http://www.cs.rpi.edu/~tayloj/
