Re: Ordered pairs

["Adam Kolany, DrAK" <kolany@ux2.math.us.edu.pl>]

> Indeed, in proving [x1,x2] = [y1, y2] implies x1 = y1 & x2 = y2 

 using the SECOND definition only !!

> one needs the regularity axiom.  But we have the axiom anyway. So,
> what is the deal? Just elegance?

when you prove the independence of the regularity you need pairs!!
besides why can't we use mathematics without regularity ? up to 
V_\omega it is provable, as I remember.

mailto:kolany@ux2.math.us.edu.pl
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