Constructing a bijection between $\mathbb N $ and the set of all subsets of finite sets of $\mathbb N $
41661
Show that the set of all finite subsets of $\mathbb{N}$ is countable.
122814
Finite Sets, Equal Cardinality, Injective $\iff$ Surjective.
150790
Prove two sets have same Cardinality by writing down bijection
15909
Bijection from $\mathbb R$ to $\mathbb {R^N}$
15733
Show that the cardinality of $\mathbb N$ is the same as the cardinality of $\mathbb N \times \mathbb N$
49953
Proving that a function from $N\times N$ to $N$ is bijective.
39231
Construct a bijection between $\mathbb{Z}^+\times \mathbb{Z}^+$ and $\mathbb{Z}^+$
102299
Bijection between $\mathbb{R}^n$ and $\mathbb{R}^m$
149673
Cardinality of an infinite union of finite sets
146436
Cardinality of the set of bijective functions on $\mathbb{N}$?
71967
cardinality of the set of $ \varphi: \mathbb N \to \mathbb N$ such that $\varphi$ is an increasing sequence
53168
Surjective, Injective, Bijective Functions from $\mathbb Z$ to itself
121685
Is there a bijection of the natural numbers which swaps $\frac{1}{n}$-summable subsets with $\frac{1}{\sqrt{n}}$-summable subsets?
155168
Is the collection of finite subsets of $\mathbb{Z}$ countable?
26569
Counting binary operations on a set with $n$ elements
113668
Uncountable chain of subsets of $\mathbb N$
12436
The cardinality of the set of all finite subsets of an infinite set