$\mathbb{R} [ X ] / ( X^ 2 + 2 )\cong \mathbb{C}$?
109610
Is $\mathbb{R}[X]/(P)$ isomorphic to $\mathbb C$ for every irreducible polynomial $P$ of degree $2?$
66313
$\mathbb{Z}[i]/(a+bi) \cong \mathbb{Z}_{a^2+b^2}$ if $(a,b)=1$
93776
Bijective mapping between $\mathbb{R}^2$ and $\mathbb{R}$?
143831
Showing $\mathbb{Q}$ is homeomorphic to $\mathbb{Q}^2$
48537
If $\forall x \in R, x^2-x \in Z(G)$, than $R$ is commutative
27056
$ gl(2,\mathbb C) \cong sl(2,\mathbb C) \oplus \mathbb C $
98587
$\mathbb Z [X] / (X)$ isomorphic to $\mathbb Z[X] / (X+1)$ isomorphic to $\mathbb Z [X] / (X+2015)$
38130
Complex structure on $\mathbb{C}\mathbb{P}^2\# \dots \# \mathbb{C}\mathbb{P}^2$
118898
Is there a simple way of proving that $\text{GL}_n(R) \not\cong \text{GL}_m(R)$?
69166
Cardinality of $\mathbb{R}$ and $\mathbb{R}^2$
44685
Inner product on $C(\mathbb R)$
128711
$(\Bbb Z\oplus \Bbb Z)[X] \not\cong \Bbb Z[X]\oplus \Bbb Z[X]\,$?
155165
Prove that $\mathbb F_8=\mathbb F_2[X]/(X^3+X+1)$
92599
Prove there generally is no isomorphism between $R[x]/(x^2-a)$ and $R^2$
108955
Showing $(\mathbb{Q},+)$ is not isomorphic to $(\mathbb{R},+)$
84869
Are the groups $\mathbb{C}$ and $\mathbb{R}$ isomorphic?
73927
Is $\mathbb{R}$ a subset of $\mathbb{R}^2$?