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RE: SUO: RE: Re: More KIF-ified Ontology Content




>
>MW: Class, a set to which we attach some significance.

Just a terminological note: this usage exactly inverts a common one 
in mathematics and set theory, where sets are a species of class, and 
there are some classes which aren't sets (roughly, becuase they are 
too big to be allowed to be counted as sets), called 'proper' classes.

I think Matthew West's usage is actually more reasonable, since it 
ties 'class' to 'classification', but it may cause some 
misunderstandings if used without explanation.

>MW: Union, the usual set theory definition. The set whose members are a
>member of one set, and or the other that you are making the union of.
>
>MW: Intersection, the set whose members are members of both sets that are
>being intersected.
> >
> > Do you have time to provide a little exposition
> > on what you mean by the "derivation" dimension?
>
>MW: a set/class whose membership can be defined in terms of other sets and
>perhaps particular objects. An easy example is a class that is defined in
>terms of the intersection of two other classes, e.g. red cars.

Ontology languages such as OIL (http://www.ontoknowledge.org/oil/ ) 
are almost entirely concerned with such 'derivation' relationships 
between classes, for example.

Pat Hayes

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