Show that is not possible to form a unity ring structure on $(\Bbb Q /\Bbb Z , + )$
30753
Showing there is no ring whose additive group is isomorphic to $\mathbb{Q}/\mathbb{Z}$
128732
$\mathbb Z_{p^n}$ is not the direct product of any family of its proper subgroups
106342
Why $L$-structures cannot satisfy a contradiction
26805
Non-Noetherian 0-dimensional ring
53331
$\mathbb{Q}(\sqrt2, \sqrt3)$ is not isomorphic to $\mathbb{Q}(\sqrt[4]2)$
95240
Show that $({\mathbb{Q}},+)$ is not finitely generated using the Fundamental Theorem of Finitely Generated Abelian Groups.
108955
Showing $(\mathbb{Q},+)$ is not isomorphic to $(\mathbb{R},+)$
113512
Characteristic of nonzero commutative rings with unity
75970
$\mathbb Z[1/2]$ is not finitely generated?
107821
The ring of integers of $\mathbf{Q}[i]$
39049
Ring With Unity As a Direct Sum of Non-Zero Ideals
25854
$\mathbb{R}^3$ \ $\mathbb{Q}^3$ is union of disjoint lines. The lines are not in an axis diretion.
98731
Show that there is no epimorphism from ($\mathbb{Q}$, +) to ($\mathbb{Z}$, +)
109987
No homomorphism from $Z_{16}\oplus Z_{2}$ onto $Z_{4}\oplus Z_{4}$.
126927
$\mathbb Q$ is not the direct product of two non-trivial groups.
88645
Prove that the additive groups $\mathbb{R}$ and $\mathbb{Q}$ are not isomorphic.
124864
A not free $\mathbb{Z}$-module