Empty VS null array?

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On Friday, 18 October 2013 at 19:59:26 UTC, H. S. Teoh wrote:
> ...because it eliminates an unnecessary distinction between an 
> empty sequence and a non-existent sequence (which then leads to 
> similar issues one encounters with null pointers).

That just seems silly. Surely we all recognize that there's a 
difference between the empty set and having no set at all, and 
that it's valuable to be able to distinguish between the two. The 
empty set is still a set, while nothing is... nothing.