On the cardinality of the set of all finite sequences of natural numbers.
12436
The cardinality of the set of all finite subsets of an infinite set
41661
Show that the set of all finite subsets of $\mathbb{N}$ is countable.
126161
Interesting property of finite integer sequence with sum 1
45460
Proof verification of a number theory problem involving sequences.
83518
Proving Two sets have same cardinality
127123
Cardinality of power set and binary sequence
66301
The cardinality of the set of countably infinite subsets of an infinite set
109968
Let $X= \{ A \subset \mathbb{N} : \mathbb{N} \backslash A \text{ is finite}\}$. What is the cardinality of $X$? Prove it.
156242
As many even numbers as natural numbers.
125683
Power set of a finite set is finite proof, no cardinality of power set
41192
Neatest proof that set of finite subsets is countable?
123847
Cardinality of $GL_n(K)$ when $K$ is finite
101993
The cardinality of a language over a set of variables $V$ with $\#V= κ$
141227
How to show the integers have same cardinality as the natural numbers?
62687
Proving Cardinality of Cosets in Abstract Algebra
45216
Cardinality of $[0,1]$
126015
Elementary number theory in sets