Proving $\mathbb{Z}[i]^{\times}$ is finite
31382
Units of Gaussian integers
46687
Elements of $GL_{2}(\mathbb{Z})$ of finite order
108044
Isomorphic extensions of $\mathbb Z_3$ by $\mathbb Z_3 \times \mathbb Z_3$ which are not equivalent
75970
$\mathbb Z[1/2]$ is not finitely generated?
86807
The units of $\mathbb Z[\sqrt{2}]$
104855
Prove that $N \subset Z(G)$
18018
Proving that $4 \mid m - n$ is an equivalence relation on $\mathbb{Z}$
31391
bijection between $\mathbb{N}$ and $\mathbb{N}\times\mathbb{N}$
74044
Find all subgroups of $\mathbb{Z}\times\mathbb{Z}$.
121141
Proving Finiteness of Group from Presentation
79056
Prove that $\mathbb Z^n$ is not isomorphic to $\mathbb Z^m$ for $m\neq n$
93621
Prove that $\mathbb{Z}[\omega]$ is an integral domain
100439
Proving that a Galois group $Gal(E/Q)$ is isomorphic to $\mathbb{F}_p^\times$
120035
Pattern in Isomorphisms between $\mathbb Z_m \times \mathbb Z_n$ and $\mathbb Z_{mn}$
15733
Show that the cardinality of $\mathbb N$ is the same as the cardinality of $\mathbb N \times \mathbb N$
39231
Construct a bijection between $\mathbb{Z}^+\times \mathbb{Z}^+$ and $\mathbb{Z}^+$
151928
How to prove that $N\setminus A$ is finite?