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Re: Fwd: Despair! The exact meaning of Complement??

From: Dave Reynolds <dave.e.reynolds@gmail.com>
Date: Sun, 27 Feb 2011 20:23:48 +0000
To: Owl Dev <public-owl-dev@w3.org>
Message-ID: <1298838228.2426.41.camel@Obsidian3>
On Sun, 2011-02-27 at 13:46 +0000, Ian Horrocks wrote: 
> Begin forwarded message:
> 
> > Resent-From: public-owl-comments@w3.org
> > 
> > From: Dave Andersen <dja222@hotmail.com>
> > 
> > Date: 25 February 2011 15:56:21 GMT
> > 
> > To: <public-owl-comments@w3.org>
> > 
> > Subject: Despair! The exact meaning of Complement??
> > 
> > 
> > Dear Working Group,
> > 
> > After fiddling a day or so away with Pellet, Hermit and Fact++ to
> > get things right (NOT!), I finally turn to you for the ultimate
> > answer for the exactdefinition of Complement:
> > Suppose I have a class Person with 9 individuals:
> > 
> > 3 with property male = TRUE, could be put in a subclass Man
> > 3 with property male = FALSE
> > 3 without a male property
> > 
> > Then WHAT is the outcome of "NOT Man" (i.e.: NOT (male value TRUE)):
> > 
> > a. the REST of the class Person, i.e. 3 with male = TRUE plus 3
> > without male property.
> > b. ONLY the 3 individuals with the property male = FALSE, since
> > FALSE is the opposite Of TRUE and can be interpreted as the
> > complement of "NOT (male value TRUE)".
> > c. NO answer at all, since it is not absolutely sure whether the 3
> > individuals without a male property mentioned here, still might have
> > it mentioned somewhere (according to OWA), but is at this moment not
> > known to the reasoner. Ergo: it can't give an answer.
> > 
> > The above reasoners give different answers or none at all! (at least
> > all different from what I myself expect: answer a.)

Is the property "male" defined as functional or not?

If not then I believe the right answer is (c) since even the individuals
with male=FALSE could have as-yet-unseen assertions male=TRUE as well.
So none of the individuals are provably members of NOT (male value
TRUE).

If "male" is functional (or subject to an appropriate cardinality
restriction), and if by TRUE/FALSE you mean either the literal boolean
values or individuals that you have declared to be disjoint, then the
answer is (b); not so much because TRUE is opposite of FALSE but because
they are disjoint and so having "male=FALSE" means those individuals
cannot also have "male=TRUE".

Dave
Received on Sunday, 27 February 2011 20:24:23 GMT

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