Why is the proof of "countable many product of countable sets is countable" wrong?
60678
Does 'A countable infinite Cartesian product of countable sets is not necessarily countable' violate induction principle?
95747
Number of countable subsets of $\mathbb{R}$
67064
Uncountable minus countable set is uncountable
155168
Is the collection of finite subsets of $\mathbb{Z}$ countable?
19297
Is the cofinite topology on an uncountable set first countable?
36315
Is $[0,1]$ a countable disjoint union of closed sets?
6161
The cartesian product $\mathbb{N} \times \mathbb{N}$ is countable
102113
Proof that the number of proofs is countably infinite
42794
Prove that functions map countable sets to countable sets
128118
Is the cofinite topology on a countable set first countable?
34998
How to prove that $\mathbb{Q}$ ( the rationals) is a countable set
134844
Summablity and countability
67066
Proof there is a 1-1 correspondence between an uncountable set and itself minus a countable part of it
122506
Relation on countable sets
118595
Proving that a set is countable by finding a bijection
44974
Infinite set and countable subsets
153652
Countable ordinals are embeddable in the rationals $\Bbb Q$ -- proofs and their use of AC