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Re: Review of RDF mapping

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Wed, 10 Sep 2008 14:23:12 -0400 (EDT)
Message-Id: <20080910.142312.220109278.pfps@research.bell-labs.com>
To: sattler@cs.man.ac.uk
Cc: public-owl-wg@w3.org

From: Uli Sattler <sattler@cs.man.ac.uk>
Subject: Review of RDF mapping
Date: Mon, 8 Sep 2008 19:12:31 +0100


> - in Table 10, if we have
> _x owl:inverseOf *:y1,
> _x owl:inverseOf *:y2
> then OPE(_x:) is, say InverseOf( OPE(*:y2)), and thus I am afraid the
> we will miss that :y1 and :y2 are equivalent?!  

Yes, this is a buglet in the reverse mapping that arises because
owl:inverseOf can arise from both axioms (InverseProperties) and
object-property expressions (InverseOf).  The solution, which I have put
in the document, is to have an additional side condition in Table 10
that OPE(_:x) is empty.  This prevents the above valid pair of triples
from not being recognized.

> The same observation
> can be made in Table 12 with ComplementOf: perhaps things like
> CE(_:x) need to be sets, and you then use the other rules on all
> elements in these sets? 

The problem only occurs with owl:inverseOf because it is used for two
things.  Other properties are not overloaded in this fashion and don't
exhibit this problem.

> Or is this related to a confusion mentioned
> above of   "The rules from the following sections are not allowed to
> redefine the value of any of these functions for some x." ? 

Not really, this wording (which I have modified to make clearer) is what
make the two example triples above result being rejected (before the
recent change).


Received on Wednesday, 10 September 2008 18:24:03 UTC

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