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Re: #rdfms-identity-anon-resources

From: Dan Connolly <connolly@w3.org>
Date: Thu, 28 Jun 2001 11:56:34 -0500
Message-ID: <3B3B61C2.1464F0BA@w3.org>
To: pat hayes <phayes@ai.uwf.edu>
CC: w3c-rdfcore-wg@w3.org
pat hayes wrote:
[...]
> i.e.
> >
> >       _:x <...prop> "val".
> >means the same thing as
> >       (exists (?x) (...prop ?x "val"))
> 
> That would mean then that it is impossible to 'use' an anonymous node
> more than once, in contrast to a genid. Is that really right?

No...

> Eg the
> anonymous node which anchors a container is referred to by more than
> one triple. Shouldn't you allow the scope of the existential to
> expand a little?

Yes; the scope of _:x is the whole list of triples,
not just one. My example was bad; to be more clear, it converts:

	_:x <mid:p1@example> "val".
	_:x <mid:p2@example> "val2".
	_:x <mid:p3@example> _:y.
	_:y <mid:p4@example> "abc".

to

(exists (?xx ?xy )
 (and 
  (PropertyValue mid\:p1\@example
     ?xx
     "val")
  (PropertyValue mid\:p2\@example
     ?xx
     "val2")
  (PropertyValue mid\:p3\@example
     ?xx
     ?xy)
  (PropertyValue mid\:p4\@example
     ?xy
     "abc")
) )

But it is true that you can't use that term ouside
the document; that's a sense in which these
things are anonymous: the syntax doesn't give
them a name in the web-wide scope.


> >i.e. to resolve this issue is to decide the formal semantics
> >of RDF. I guess I can work with Graham on this abstract
> >syntax and formal semantics stuff. [Graham, please let's
> >keep reification outa there.]

[...]

> >My position is represented by my n-tripes2kif.pl code;

I neglected to include a pointer:
  http://www.w3.org/2000/10/swap/n-triples2kif.pl

and I'll excerpt a bit to be precise about what I
mean by "n-triples" and "KIF":

#!/usr/bin/perl
#
# converts n-triples to KIF
#
# USAGE:
#  perl n-triples2kif.pl <foo.nt > foo.kif
#
# REFERENCES
#  n-triples:  working specification
#    is a message I sent 30 May
#   
http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001May/0264.html
#    ratified in RDF Core WG 1 Jun telcon
#   
http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Jun/0008.html "
#
#  KIF
#    Knowledge Interchange Format draft proposed American National
Standard (dpANS)
#    NCITS.T2/98-004
#    Last Modified: Thursday, 25-Jun-98 22:31:37 GMT 
#    http://logic.stanford.edu/kif/dpans.html
#
# TODO:
#  integrate this into cwm? offer the resulting RDF->KIF
#  conversion as an HTTP service?
#  ... other issues noted @@ below
#
# $Id: n-triples2kif.pl,v 1.4 2001/06/07 20:03:37 connolly Exp $
# see changelog at end

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Thursday, 28 June 2001 12:56:37 EDT

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