Re: AtomList infinite or cyclic in all models

> [Bijan Parsia]
> 
> [...]
> However, another way to deal with your specific issue is to make #nil  
> related by first and rest to itself. Indeed, nothing prevents cyclic  
> models, as you said. In some Lisps, for example, ...

Yikes!  This is just a (notorious) hack, and doesn't solve, or even
address, the problem.  The idea of letting the 'car' and 'cdr' of nil
be nil is a "convenience," and not true to the semantics of nil qua
empty list at all.  It can't be literally true that the empty list is
equal to the "list" with itself as head and tail, and if it were then
testing whether a list was empty would be a nightmare.

-- 
   Drew McDermott
   Yale Computer Science Department