Is $\mathbb{Z}[\sqrt{-1}]/(7)$ isomorphic to $\mathbb{Z}[\sqrt{-2}]/(7)$?
40400
Finding an isomorphism between $\mathbb{Z}[i]/(7)$ and $\mathbb{Z}[\sqrt{-2}]/(7)$
108955
Showing $(\mathbb{Q},+)$ is not isomorphic to $(\mathbb{R},+)$
19230
Prime/Maximal Ideals in $\mathbb{Z}[\sqrt d]$
95863
Describe the units in $\mathbb{Z}[\sqrt{-d}]$
16507
Is $\mathbb{Z}= \{\dots -3, -2, -1, 0 ,1 ,2 , 3, \dots \}$ countable?
8434
Order of $\mathbb{Z}[i]/(1+i)$
81238
Is $O(2)$ really not isomorphic to $SO(2)\times \{-1,1\}$?
118073
Is the ring $m\mathbb{Z}$ isomorphic to the ring $n\mathbb{Z}$?
66313
$\mathbb{Z}[i]/(a+bi) \cong \mathbb{Z}_{a^2+b^2}$ if $(a,b)=1$
42810
Is $(\mathbb{Q},+)$ isomorphic to $(\mathbb{Q}^n,+)$?
138256
What's the difference between $\mathbb{Q}[\sqrt{-d}]$ and $\mathbb{Q}(\sqrt{-d})$?
3317
Subgroup generated by $2$ and $7$ in $(\mathbb Z,+)$
37928
Isomorphism between $D_{2n}/Z(D_{2n})$ and $D_n$
158315
Are $M_2= \langle(\sqrt{2}^{\sqrt{2}},\infty),\cdot \rangle$ , $M_1 = \langle(2,\infty),\cdot\rangle$ isomorphic structures?
51695
Finding all homomorphisms between $\mathbb{Z}/m\mathbb{Z}$ and $\mathbb{Z}/n\mathbb{Z}$
23879
If $m$ and $n$ are distinct positive integers, then $m\mathbb{Z}$ is not ring-isomorphic to $n\mathbb{Z}$
68915
What are the units in $\mathbb{Z}[\root 3 \of 2]$?