Show that these rings are not isomorphic
12110
How are $2\mathbb{Z}\ncong3\mathbb{Z}$ different as rings?
26661
Ring homomorphisms from $\mathbb{Z}_n$ to $\mathbb{Z}_m$
60925
Why these are isomorphic each other for given these rings?
18160
How to show that the group of nonzero real numbers under multiplication is not isomorphic to the group of real numbers under addition?
148616
When is a ring homomorphism $A \to A$ surjective but not injective.
78873
How to show that the monomials are not a Schauder basis for $C[0,1]$
97999
Explain these ring isomorphisms
113413
How do I show that two groups are not isomorphic?
77112
Artinian rings that are not Artin algebras
88645
Prove that the additive groups $\mathbb{R}$ and $\mathbb{Q}$ are not isomorphic.
51861
$S_4$ is not isomorphic to $D_{12}$
132386
Show that $(\mathbb{Q}^*,\cdot)$ and $(\mathbb{R}^*,\cdot)$ aren't cyclic
30753
Showing there is no ring whose additive group is isomorphic to $\mathbb{Q}/\mathbb{Z}$
120155
How to show that this group presentation is isomorphic to dihedral group?
85586
Proving $\mathbb{Q}$ isn't homeomorphic to $\mathbb{Z}$
23879
If $m$ and $n$ are distinct positive integers, then $m\mathbb{Z}$ is not ring-isomorphic to $n\mathbb{Z}$
53331
$\mathbb{Q}(\sqrt2, \sqrt3)$ is not isomorphic to $\mathbb{Q}(\sqrt[4]2)$