Prove that $\{X \in P(Z)| X \text{ is finite}\}$ is enumerable.
41661
Show that the set of all finite subsets of $\mathbb{N}$ is countable.
68430
Proving the countability of algebraic numbers
35692
The set of all finite subsets of the natural numbers is countable
91947
Proof of $ f:I_n \rightarrow I_m \Rightarrow n = m$
140430
Let $E = \mathbb{Q}\big(\left\{\sqrt[n]{2} \mid n \in \mathbb{N} \setminus \left\{0\right\} \right\} \big)$. Prove $[E: \mathbb{Q}]$ is not finite
94413
Proving Dedekind finite implies finite assuming countable choice
119549
Prove the even integers are countable (by explicitly giving a bijection $\mathbb{N} \to E$)
122814
Finite Sets, Equal Cardinality, Injective $\iff$ Surjective.
34998
How to prove that $\mathbb{Q}$ ( the rationals) is a countable set
124333
A bijection between $\mathbb{N}$ and $\mathbb{P}(\mathbb{N})$?
59724
Proving that $x_n\to L$ implies $|x_n|\to |L|$, and what about the converse?
53244
Prove that $p \in \mathbb{R}[x]$ can be represented as a sum of squares of polynomials from $\mathbb{R}[x]$
78117
Closed property of nonempty finite set
110876
Prove that $p\mid \binom{p}{k},\ 0< k< p$
52865
Topological Vector Space: $\dim Z\text{ finite}\implies Z\text{ closed}$
68139
Show that the set of polynomials with rational coefficients is countable.
37183
Show that the set of all $x$ such that $x \in P$ and $x \notin Q$ exists