- From: Dan Connolly <connolly@w3.org>
- Date: Mon, 30 Apr 2007 21:12:24 -0500
- To: Sandro Hawke <sandro@w3.org>
- Cc: timbl@w3.org, public-cwm-talk@w3.org
On Mon, 2007-04-30 at 20:17 -0400, Sandro Hawke wrote:
>
> Here's a test (motivated by a current discussion in RIF-WG):
>
> <a> <b> <c>.
> <a> <b> <d>.
> { <a> <b> ?x } => { _:x <b_inferred> ?x. }.
> _:x <b_given> <c>.
> _:x <b_given> <d>.
>
> The (relevant) output I get from cwm is:
>
> [ <b_given> <c>, <d> ].
> [ <b_inferred> <c> ].
> [ <b_inferred> <d> ].
>
> which makes it clear that the "_:x" inside the rule conclusion does not
> name the same thing as the other "_:x"'s in the file do. In other
> words, b-nodes in rule conclusions get an implicit existential
> quantifier inserted. They don't just use the implicit one around the
> file.
>
> Two questions: (1) is that as it should be?
yes, I'm pretty sure that's by design.
I'm pretty sure we captured that design decision in tests.
> (2) how strongly do you feel that way? (would it
> be reasonable to do it the other way, perhaps?)
It might be reasonable to say "don't do that" in response
to using _:x in different scopes, but I don't
think it's reasonable to use the syntax above to mean something else.
--
Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541 0875 0F91 96DE 6E52 C29E
Received on Tuesday, 1 May 2007 02:12:28 UTC