Homomorphism between $\mathbb{Z}_m$ and $\mathbb{Z}_n$ if $m\mid n$
5906
All group homomorphism from $ \mathbb{Z} _m $ to $\mathbb{Z}_n $
83001
Easier way to show $(\mathbb{Z}/(n))[x]$ and $\mathbb{Z}[x] / (n)$ are isomorphic
45627
Find a sub-ring of M(2, $\mathbb{Q}$) which is isomorphic to $\mathbb{Q}$
93169
Show that $(\mathbb Z[x],+)$ and $(\mathbb Q_{>0},\cdot)$ are isomorphic groups
114916
$\mathbb Z_{mn}$ isomorphic to $\mathbb Z_m\times\mathbb Z_n$ whenever $m$ and $n$ are coprime
48397
Index of a sublattice in a lattice and a homomorphism between them
18018
Proving that $4 \mid m - n$ is an equivalence relation on $\mathbb{Z}$
37928
Isomorphism between $D_{2n}/Z(D_{2n})$ and $D_n$
1026
Ring homomorphism with $\phi(1_R) \neq1_S$
141984
Find the number of homomorphisms between $\mathbb{Z}_m$ and $\mathbb{Z}_n$
102299
Bijection between $\mathbb{R}^n$ and $\mathbb{R}^m$
30327
$\ker \phi = (x_1-a_1, ..., x_n-a_n)$ for a ring homomorphism $\phi: R[x_1, ..., x_n] \to R$
40490
Birational isomorphism $\mathbb{P}^n\times \mathbb{P}^m\to \mathbb{P}^{n+m}$
145722
Prove there is a bijection between the set of $R[x]$-module structures on $M$ and $\mathrm{End}_{R-\mathsf{Mod}}(M)$.
79056
Prove that $\mathbb Z^n$ is not isomorphic to $\mathbb Z^m$ for $m\neq n$
129858
"Almost" ring homomorphism
88930
Homomorphism between free groups