Definition talk:Rank (Set Theory)

Doesn't $A$ have to be a set, rather than a class, in order for it to be an element of something? What is the point of starting out supposing it to be a class? --Dfeuer (talk) 21:06, 25 December 2012 (UTC)
 * In my book, yes. Recall that I described this part of the wiki as 'wobbly' yesterday. There's much work to be done. --Lord_Farin (talk) 22:05, 25 December 2012 (UTC)
 * I'm working on it. Unfortunately, there's wobbliness all the way down to the definitions and axioms, and, furthermore, it seems that every source axiomatizes set theory a bit differently in order to confuse matters as effectively as possible. I corrected this page.--Dfeuer (talk) 22:46, 25 December 2012 (UTC)


 * Incompletely - there is still a reference to a "class" in the Notation section.


 * Bear in mind that part of its wobbliness is the fact that it duplicates some of the more solidly put together set-theory work in the language of class theory. IMO those approaches need to be merged, but exactly how this is to happen has not been decided. --prime mover (talk) 00:00, 26 December 2012 (UTC)