If α is a unit in $\mathbb{Z}[\sqrt2]$ then $a^2 - 2b^2 = \pm1$
86807
The units of $\mathbb Z[\sqrt{2}]$
91113
$ \exists a, b \in \mathbb{Z} $ such that $ a^2 + b^2 = 5^k $
106584
If $A^{2n}=I$, then $A^n=\pm I$ where $A\in M_n(\mathbb{R})$
92583
Prove that $N(\gamma) = 1$ if, and only if, $\gamma$ is a unit in the ring $\mathbb{Z}[\sqrt{n}]$
135441
When is $\mathbb{Z}[\alpha]$ dense in $\mathbb{C}$?
114346
Why is $a^{-1}$ mod $p$ equal to $a^{p-2}$ mod $p$?
90486
If $(A-B)^2=O_2$ then $\det(A^2 - B^2)=(\det(A) - \det(B))^2$
118304
If $A^2 = I$ (Identity Matrix) then $A = \pm I$
91101
Proving $\sqrt2$ is irrational
7491
How to show that $7\mid a^2+b^2$ implies $7\mid a$ and $7\mid b$?
61987
$x^2+1=0$ in $\mathbb{Z}_7$
26749
$\mathbb{Z}[X]/(X^2-1)$ is not isomorphic with $\mathbb{Z}\times \mathbb{Z}$
13162
Prove $\alpha \in R[[x]]$ is a unit iff $a_0 \in R$ is a unit
52658
What are the integer solutions to $a^{b^2} = b^a$ with $a, b \ge 2$
6837
How to quotient $\mathbb Z [\sqrt{-11}] / (1+\sqrt{-11})$?
112043
Show that the ideal $ (2, 1 + \sqrt{-7} ) $ in $ \mathbb{Z} [\sqrt{-7} ] $ is not principal
93031
How to show that $\mathbb{Z}$ with the operation $m*n=m+(-1)^m n$ is associative?