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Re: scope of _:existentials in N3Logic?

From: Dan Connolly <connolly@w3.org>
Date: Fri, 26 Feb 2010 09:17:51 -0600
To: Tim Berners-Lee <timbl@w3.org>
Cc: public-cwm-talk@w3.org
Message-ID: <1267197471.30230.503.camel@pav.lan>
On Fri, 2010-02-26 at 10:00 -0500, Tim Berners-Lee wrote:
> That example is confusingly written, because _:somebody 
> means something different in the different contexts.

Well, sure, I know that now... but the exercise here
is a clean-room implementation of N3. Where is the
scope of _:somebody specified?

> a _:foo always is a local bnode within the graph.

but "the graph" is ambiguous; _:somebody is in 2 graphs.


> If  the effect you were aiming for was to refer in the rule
> to the same variable, then you have to explicitly quantify it in the
> outermost graph:
> 
> 
> $ cat varscope1a.n3 
> @prefix : <evarscope1#>.
> @keywords is, of, a.
> 
> @forSome somebody.
> bob likes somebody.
> fred likes somebody.
> { alice likes ?X } => { ?X likes somebody }.
> alice likes trina.

OK, that makes sense.


-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
gpg D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Friday, 26 February 2010 15:17:53 GMT

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