Re: subclass loops, proper subclasses and so on

From: pat hayes (
Date: 08/28/01

> > 1. What reason can there be to forbid subclass loops, other than
> > subClassOf being understood to mean proper subclass?
>Several possibilities:
>1) Tools that traverse inheritance hierarchies have to
>explicitly handle cycles rather than just recurse.  This
>could break current RDFS tools.
>2) Subclass loops often indicate a design error or a
>partially applied change.
>3) Java and C++ programmers don't expect subclass cycles.
> > So, what justification can there be for asserting that
> > rdfs:subClassOf does *not* mean proper subclass?
>Richard and I had the same question (a good sign for me):
>Does "proper subclass" imply the (possible) existance of
>some instance that is a member of the class but not of the

Yes. The actual existence, in fact. Mind you, that instance might not 
have anything referring to it.


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