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RE: Why Triples? (was Re: What do the ontologists want)

From: <jos.deroo.jd@belgium.agfa.com>
Date: Sun, 20 May 2001 14:03:10 +0100
To: ziv@unicorn.com
Cc: sandro@w3.org, www-rdf-logic@w3.org
Message-Id: <OFCCBE745C.C5676838-ON41256A52.00458F5A@bayer-ag.com>

> If you do want to speak of attributes here, you must assign them to
> tuples: you _can_ meaningfully ask "what film is showing {in April,
> in Tel Aviv, in the Globus cinema, in theatre 1} and get a clear
> answer: "Pokemon 2", and then it does begin to resemble your example
> of the objects with colour, size, and so forth. But then the assignments
> are to tuples, not single atomic objects, and do not form natural
> ground atom triples. And this way of viewing the table is not unique
> either -- there could possibly be other attribute assignments to other
> types of tuples.

We can imagine all kinds of queries for that example
e.g. the possibility to use fewer parameter properties
in a query (or extra parameter properties in the facts)
or swapping the position of parameter properties or
using synonyms for parameter property names (such as
:month = :maand.) etc.
So if we have http://www.agfa.com/w3c/n3/ziv.n3
we could ask the query http://www.agfa.com/w3c/n3/ziv-query.n3

C:\n3>java Euler http://www.agfa.com/w3c/n3/ziv.n3 http://www.agfa.com/w3c/n3/zi
# Generated with Euler 26.047 on Sun May 20 13:52:46 CEST 2001
# @prefix log: <http://www.w3.org/2000/10/swap/log.n3#>.
# @prefix : <http://www.agfa.com/w3c/n3/ziv.n3#>.
# {[ :maand "May"; :city :c; :film :f; :cinema "Globus"]  } log:forAll :c, :f.

@prefix log: <http://www.w3.org/2000/10/swap/log.n3#>.
@prefix : <http://www.agfa.com/w3c/n3/ziv.n3#>.

[ :maand "May"; :city "Tel Aviv"; :film "Pokemon 2"; :cinema "Globus"]  .

[ :maand "May"; :city "Tel Aviv"; :film "Billy Elliot"; :cinema "Globus"]  .

[ :maand "May"; :city "Tel Aviv"; :film "The Mummy"; :cinema "Globus"]  .

[ :maand "May"; :city "Jerusalem"; :film "A Hard Day's Night"; :cinema "Globus"]

[ :maand "May"; :city "Jerusalem"; :film "15 Minutes"; :cinema "Globus"]  .

# Proof found for http://www.agfa.com/w3c/n3/ziv-query.n3 in 18 steps (3603 step

Now this is RDF/N3 with binary predicates (and using resolution
for anonymous nodes which is indeed as Pat says
"""In general, the more stuff you can incorporate into the unifier,
   the more efficient the inference search: you tend to be trading
   an exponential for a linear cost, a very good trade.""")

Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Sunday, 20 May 2001 08:03:34 UTC

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