Talk:Countable Union of Countable Sets is Countable/Informal Proof

Unless I'm missing something, Countable Union of Countable Sets is Countable/Proof 1 is basically, if not exactly, a formalized version of this argument. That's the reason that I replaced this argument with that one. Comments? --abcxyz (talk) 17:00, 14 December 2012 (UTC)


 * You appear to be right. In fact, gave this argument, but I added the reference to Proof 1. That's how close they are. Maybe the only merit this has lies in an "informal proof" section. --Lord_Farin (talk) 17:03, 14 December 2012 (UTC)


 * You are completely correct. But why is this a problem? --prime mover (talk) 19:44, 14 December 2012 (UTC)


 * So why does this page even exist? Not that there's a problem, but I just don't understand. --abcxyz (talk) 22:02, 14 December 2012 (UTC)


 * Why should it not? --prime mover (talk) 22:06, 14 December 2012 (UTC)


 * Because it's (arguably) the same proof. If we were to provide rigorous justification for every step (particularly the one involving the diagram), which is apparently one of the ideas of ProofWiki, this would just become Proof 1. --abcxyz (talk) 22:13, 14 December 2012 (UTC)

Agreed. As I pointed out above, this can only be justifiably retained if it is transformed into an "informal" or "intuitive" proof, of the kind some other theorems have. --Lord_Farin (talk) 22:14, 14 December 2012 (UTC)