View source for Talk:Countable set

==Countable vs counted==
Some authors distinguish between a countable set and a ''counted'' set, a pair $(X,f)$ consisting of a set $X$ and a bijection between $X$ and (a subset of) the set $\mathbf{N}$ of natural numbers: the theorem that is mentioned then becomes that a counted union of counted sets is counted.  [[User:Richard Pinch|Richard Pinch]] ([[User talk:Richard Pinch|talk]]) 20:44, 18 January 2018 (CET)

====References====
* T.E Forster, "Logic, Induction and Sets", Cambridge University Press (2003) ISBN 0-521-53361-9