[protege-discussion] Nothing class (newbie question)

[Matthew Horridge]

Hi,

owl:Nothing is interpreted as the empty set.  It does not have any instances.  Because it is interpreted as the empty set, it is a subclass of every other class (since the empty set is a subset of every set).  owl:Thing appears at the top of the class hierarchy, whilst owl:Nothing appears at the bottom of the class hierarchy.  Hope this helps.

Cheers,

Matthew



On 6 Mar 2013, at 11:12, André Luiz Tietböhl Ramos wrote:

> Hello,
> 
> What does the Nothing class mean actually?  Assuming its superclasses are inferred, I have many in it and do not know what this aspect means for sure.
> 
> Thanks in advance.
> 
> -- 
> André Luiz Tietböhl Ramos
> http://www.feng.pucrs.br/~andreltr
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