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QCR problem in OWL 1.1 Full - action ?? from F2F

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 07 Dec 2007 09:23:59 -0500 (EST)
Message-Id: <20071207.092359.204634082.pfps@research.bell-labs.com>
To: ian.horrocks@comlab.ox.ac.uk
Cc: public-owl-wg@w3.org

Qualified Cardinalities in OWL 1.1 Full


Suppose that we want to keep the general flavour of the OWL Full
semantics *and* use the current OWL 1.1 mapping to RDF.  What would
happen?


Here is an example of how the RDF mapping works (roughly). 

ObjectMaxCardinality(2 child) expands to:

_:x rdf:type owl:Restriction
_:x owl:maxCardinality "2"^^xsd:nonNegativeInteger
_:x owl:onProperty child

ObjectMaxCardinality(2 child Person) expands to:

_:y rdf:type owl:Restriction
_:y owl:maxCardinality "2"^^xsd:nonNegativeInteger
_:y owl:onProperty child
_:y owl11:onClass Person

Note especially that the first set of triples is a "subset" of the
second set.


The OWL 1.0 Full semantics says that the class extension of _:x is the
set of objects that are related to at most two objects via the property
extension of child.  A similar-style OWL 1.1 Full semantics would say
that the class extension of _:y is the set of objects that are related
to at most two objects that belong to the class extension of Person via
the property extension of child.

However, the OWL 1.1 Full semantics would then also include the OWL 1.0
Full semantics.  So, part of the meaning of the last four triples
(actually the first three of these four, but that doesn't matter) in OWL
1.1 Full would be that the class extension of _:y would *as well* be the
set of objects that are related to at most 2 objects via the property
extension of child.

So, if o is in the class extension of _:y then it is related to at most
two objects that belong to the class extension of Person via the
property extension of child *and* it is related to at most two objects
via the property extension of child.  It is impossible to have a max-QCR
without this double meaning.



peter
Received on Friday, 7 December 2007 14:43:20 GMT

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