Cardinality of the union of all repeated Cartesian products of N with itself
84936
The set of all finite sequences of members of a countable set is also countable
130156
Image of the union and intersection of sets.
45216
Cardinality of $[0,1]$
70164
Proof exercise that the cardinal number of a set in $\mathbb R^2$ is $\frak c$
50880
Expressing $\Bbb N$ as an infinite union of disjoint infinite subsets.
89506
Union of disjoint sets : Equivalence relations
114262
Find the cardinality of the following set $S_n=\{(x,y)|x^2+y^2=n, \text{where }x,y,n \in \mathbb Z\text{ and }n\geq0 \}$
62687
Proving Cardinality of Cosets in Abstract Algebra
83518
Proving Two sets have same cardinality
6161
The cartesian product $\mathbb{N} \times \mathbb{N}$ is countable
13398
Prove that the interval $(0, 1)$ and the Cartesian product $(0, 1) \times (0, 1)$ have the same cardinality
154698
Union of Cartesian products: $X \times (Y \cup Z)= (X \times Y) \cup(X\times Z)$
14711
set theoretic function, products of sets (product versus Cartesian product)
111954
Computing the cardinality of a combinatorial set
127123
Cardinality of power set and binary sequence
101993
The cardinality of a language over a set of variables $V$ with $\#V= κ$
86914
Cardinality of the set of hyperreal numbers