Talk:Pair is Union of Singletons

Why need to state $x \ne y$? If $x = y$ the equality holds.


 * But then it jsut equals $\left\{{x}\right\}$. --prime mover (talk) 15:06, 14 October 2016 (EDT)


 * But we avoid embarrassing assumption. --Grzegorz Bancerek (talk) 11:52, 15 October 2016