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Reminder: pending discussion "membership" (pending discussion on ACTION-350)

From: Axel Polleres <axel.polleres@deri.org>
Date: Fri, 07 Dec 2007 00:04:00 +0000
Message-ID: <47588DF0.3000600@deri.org>
To: "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>

Dear all,

I was asked by Chris to remind again to forward again a reminder on the 
pending discussion about the special notation '#' for class membership 
and in RIF since this should be discussed in the upcoming Teleconf.

In the last f2f I was asked to send a use case for this, where I sent 
the - obvious - RDF use case, see

For your convenience I copy this here again:



The class membership notation '#' is intended to reflect the common
feature of many rule and object oriented languages for being able to
express memebership of a class (or type?)

A possible use for this is for RDF's rdf:type construct...

To reflect this in the current RDF/RDFS embeddings, one could add to

1) Add to RDF embedding:

    Forall ?c,?o ?o#?c :- ?o[rdf:type -> ?c]

------- ACTION done, what follows is additional discussion ;-) --------

This alone, obviously doesn't make too much sense, but in connection
with the additional subclass notation '##' one could safe two rules
in the RDFS embedding:

2) Add to RDFs embedding:

   Forall ?c1,?c2 ?c1##?c2 :- ?c1[rdfs:subclassOf-> ?c2]

and remove:
   Forall ?x,?y,?z ?z[rdf:type -> ?y] :- And (?x[rdfs:subClassOf -> ?y]
?z[rdf:type -> ?x]),
   Forall ?x,?y,?z ?x[rdfs:subClassOf -> ?z] :- And (?x[rdfs:subClassOf
-> ?y] ?y[rdfs:subClassOf -> ?z]),

In total, the use of the special notation adds two rules and saves us
two rules in the RDF/RDFS embedding.

Pretty much equals out ;-)

That's why I am absolutely neutral on whether we chould keep that
feature or no.


p.s.: Note that I have to send regrets for the next Telecon, since I 
will be travelling most likely (could be I get connection from train or 
airport, but no guarantees.)

Dr. Axel Polleres
email: axel@polleres.net  url: http://www.polleres.net/
Received on Friday, 7 December 2007 00:04:24 UTC

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