Show that $\overline{x}\in\Bbb Z/(n\Bbb Z)$ is invertible iff $\gcd(x,n)=1$
123482
How to compute $\mathbb{Z}_n^*$, the unit group of the integers modulo $n$?
96398
An integer $a \pmod m$ has inverse if and only if $\gcd(a,m)=1$?
2043
$X^n-Y^m$ is irreducible in $\Bbb{C}[X,Y]$ iff $\gcd(n,m)=1$
128966
Explicit bijection between $\Bbb R$ and permutations of $\Bbb N$
107842
Behaviour of ($\overline{a}_n)_{n=1}^{\infty}$ and ($\underline{a}_n)_{n=1}^{\infty}$
116630
Antiderivative $1/z$ on $\mathbb C$
14161
Proof of when is $A=X^TX$ invertible?
48585
Proving that if $G/Z(G)$ is cyclic, then $G$ is abelian
28021
Showing that these two definitions of $\gcd(a,b)$ are equivalent
106101
Why there is much interest in the study of $\operatorname{Gal}\left(\overline{\mathbb Q}/\mathbb Q\right)$?
106398
If $A$ is invertible show that $\det(A) \neq 0$
24845
Let $a\mid c$ and $b\mid c$ such that $\gcd(a,b)=1$, Show that $ab\mid c$
110313
Prove that $\gcd(f(x),g(x)) = 1$.
74631
For natural numbers $a$ and $b$, show that $a \Bbb Z + b \Bbb Z = \gcd(a, b)\Bbb Z $
41742
inverse limit of $k[x]/(x^n)$
158695
Prove that if $AB$ is invertible then $B$ is invertible.
51952
Show that $x^{n-1}+\cdots +x+1$ is irreducible over $\mathbb Z$ if and only if $n$ is a prime.