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Re: what RDF is not (was Re: RDF/XML Syntax Specification (Revised) W3C Working Draft published)

From: <jos.deroo.jd@belgium.agfa.com>
Date: Thu, 20 Dec 2001 22:15:53 +0100
To: pfps@research.bell-labs.com
Cc: bwm@hplb.hpl.hp.com, mmoran@netphysic.com, dave.beckett@bristol.ac.uk, www-rdf-interest@w3.org
Message-Id: <OFE0E725E1.427C3F02-ONC1256B28.00744F99@bayer-ag.com>

> How is your solution any different from the solution to a related problem
below?
>
> As far RDF is concerned both solutions depend on magic.
>
> peter
>
>
>
> Question:
>
> RDF does not have arbitrary first-order formulae?

Indeed (but...)

Let's take graph1 (but not assert it)

  _:child gc:childIn _:family .
  _:parent gc:spouseIn _:family .

and let's take graph2 (but not assert it)

  _:aaa gc:parent _:bbb .

and let's

  o assume that bnode _:child is same thing as bnode _:aaa
  o assume that bnode _:parent is same thing as bnode _:bbb
  o assert that graph1 logically implies graph2

From the ``implies'' scope the bnodes in graph1
are actually universally quantified variables
(and in this case also the bnodes of graph2
but not in the general case, where they
are only existentially quantified).
That is a FOL entailment rule
which we can simply write as

  { ?child gc:childIn ?family . ?parent gc:spouseIn ?family }
    log:implies { ?child gc:parent ?parent } .

No?

--
Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Thursday, 20 December 2001 16:18:06 GMT

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