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

From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Date: Sun, 27 Feb 2011 13:46:09 +0000
To: Owl Dev <public-owl-dev@w3.org>
Message-Id: <2FBFFA1A-90DD-4E20-920C-0D19080ED042@comlab.ox.ac.uk>
```Begin forwarded message:

> From: Dave Andersen <dja222@hotmail.com>
> Date: 25 February 2011 15:56:21 GMT
> 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.)
>
> Another question: is W3C Monotonicity defined as strictly decreasing/increasing (staying equal NOT allowed) or nonincreasing/decreasing (staying equal allowed)?
> And another: Is it allowed to make the most upper class "Thing" equivalent to a defined class?
>
> Thank you very much in advance,
>
> DJ
>
```
Received on Sunday, 27 February 2011 13:46:40 UTC

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