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[OEP] QCR editor's draft review

From: <jpan@csd.abdn.ac.uk>
Date: Thu, 22 Dec 2005 11:08:14 +0000
Message-ID: <20051222110814.sto5wr7eh2isk8ss@www.csd.abdn.ac.uk>
To: Alan Rector <rector@cs.man.ac.uk>, Guus Schreiber <schreiber@cs.vu.nl>
Cc: public-swbp-wg@w3.org


This is a review of the QCR draft at

http://lists.w3.org/Archives/Public/public-swbp-wg/2005Nov/att-0022/QCRs-revised-01.html

This is an interesting draft which provides three possible ways to represent
some levels of QCRs. I like it very much and I hope the following comments
below could help further improve the quality of the draft.

Jeff



Major Comments
=============

* Pattern 2

1. Title of Pattern 2 is not very precise as we use more than just subPropertyOf
axioms; e.g., we also use range axioms in this trick. I suggest we adjust the
words a bit and use, e.g.,

'Work around' using sub-properties

as the title of Pattern 2.

2. The example used in the Discussion can be extended with some facts (see
below) which could made it clearer why the trick sometimes is not enough.

Give the following class axiom

Class( Minimal_Italian_Dinner partial
    intersectionOf(
        Restriction(  has_starter cardinality(1))
        Restriction(  has_main_course cardinality(1))
        Restriction(  has_desert cardinality(1))
        Restriction(  has_course someValuesFrom(IceCream_course) ))),

the (subPropertyOf and range) property axioms about has_starter,
has_main_course, has_desert and has_course axioms) and the following facts

Individual (dinner1 value(has_starter s1)
                    value(has_main_course m1)
                    value(has_desert d1)
                    value(has_course Individual (c1 type(IceCream_course))))

DifferentIndividuals(c1 d1),

we have dinner1 as an instance of the Minimal_Italian_Dinner class, even if
IceCream_course is a sub-class of Desert. Note that different sub-properties of
has_course **can** have the same range; therefore, the above axioms do not
entail that dinner has_desert c1.

This example indicates that the use of the super property can easily open a back
door for unintended individuals.

3. Another side affect of this trick is the introduce of (unnecessary) global
range constraints (for the new sub-properties). Note that QCRs are simply some
local constraints.


* Pattern 3

1. Following the style of the first two patterns, we should introduce the
abstract syntax first, then RDF syntax.

2. There might be an issue of the abstract syntax: valuesFrom is not included in
the OWL standard (there exist allValuesFrom and someValuesFrom, but no
valuesFrom). Therefore, it might not be legal in OWL Full.


Minor Comments
=============

1. The title tag needs to be updated.

2. OWL abstract syntax: unbalance brackets, "," after the property URI in a
restriction (and there should not be).
Received on Thursday, 22 December 2005 11:10:04 UTC

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