Bijection between $\mathbb{N}$ and $\mathbb{N}^n$ for any $n\in\mathbb{N}$.
32774
Finite Cartesian Product of Countable sets is countable?
67644
How does one get the formula for this bijection from $\mathbb{N}\times\mathbb{N}$ onto $\mathbb{N}$?
109710
Bijection between $\mathbb N \times \mathbb N$ and $\mathbb N$
21663
Bijection between power sets of sets implies bijection between sets?
141984
Find the number of homomorphisms between $\mathbb{Z}_m$ and $\mathbb{Z}_n$
64140
Find a bijection from $\mathbb R$ to $\mathbb R-\mathbb N$
133699
Proving that there is a bijection between $A$ and $B$.
128966
Explicit bijection between $\Bbb R$ and permutations of $\Bbb N$
119648
For which $n$ and $k$ are there nontrivial homomorphisms from $S_n$ to $\mathbb{Z}/k\mathbb{Z}$?
97878
Are there uncountably many surjections from $\mathbb N$ to $\mathbb N$?
72642
Continuous bijection from $(a,b) \to S^1$?
78847
Bijection between Prime numbers and Natural numbers
130137
How to define a Bijection between $(A^B)^C$ and $A^{B \times C}$
141799
Is $2^{|\mathbb{N}|} = |\mathbb{R}|$?
102299
Bijection between $\mathbb{R}^n$ and $\mathbb{R}^m$
143069
What are the direct summands in $\mathbb{Z}^n$?
23464
How to find a explicit bijection for some $f:A\times B \rightarrow B \times A$