Talk:Countable set
From Encyclopedia of Mathematics
The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.
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. Richard Pinch (talk) 20:44, 18 January 2018 (CET)
- True; and the latter form of the theorem does not depend on the (countable) choice axiom, unlike the "usual" form. Boris Tsirelson (talk) 21:59, 18 January 2018 (CET)
References
- T.E Forster, "Logic, Induction and Sets", Cambridge University Press (2003) ISBN 0-521-53361-9
How to Cite This Entry:
Countable set. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Countable_set&oldid=42750
Countable set. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Countable_set&oldid=42750