There is no commutative ring whose group of units is isomorphic to $\mathbb{Z}/p^2\mathbb{Z}$
61391
Which finite groups are the group of units of some ring?
128732
$\mathbb Z_{p^n}$ is not the direct product of any family of its proper subgroups
85032
$Q(\mathbb{Z}[t]) / \mathbb{Z}[t]$ is not injective
88474
$\mathbb{A}^{2}$ not isomorphic to affine space minus the origin
158873
Is every group the unit group of some ring?
66169
Ring of order $n$ is isomorphic to $\Bbb Z/n\Bbb Z$, with $n$ square-free
146334
Are there fields $F$ such that the rings $F[x]/(x^2)$ and $F[x]/(x^2-1)$ are isomorphic?
28210
A finite group with exactly $2$ conjugacy classes isomorphic to $\mathbb{Z}_2$
3213
There exists only two groups of order $p^2$ up to isomorphism.
33781
Is $\mathbb{Z}[x]/(x^2+1)$ isomorphic to $\mathbb{Z}[i]$?
80849
There does not exist group $G$ such that Aut$(G)\cong \mathbb{Z}_n$ (for odd $n$)
19884
The units of $\mathbb Z_4[x]$
120557
Group of invertible elements of a ring has never order $5$
92420
Characteristic of  a Non-unital Integral Ring
61084
Examples of non-isomorphic fields with isomorphic group of units and additive group structure
92822
Finite number of elements generating the unit ideal of a commutative ring
8587
What is an example of two k-algebras that are isomorphic as rings, but not as k-algebras?