$\mathbb{Q} \simeq \mathbb{Q}^*_+$ isomorphism
86542
Group of positive rationals under multiplication not isomorphic to group of rationals
109596
Isomorphism from $\mathrm{Aut}(\mathbb{Z}/2\mathbb{Z}\times \mathbb{Z}/2\mathbb{Z})$ to $S_3$
115663
Proving an isomorphism using the isomorphism theorems
23279
Group Theory Isomorphism
145752
Aut $\mathbb Z_p\simeq \mathbb Z_{p-1}$
154847
homomorphism from $S_3$ to $\mathbb Z/3\mathbb Z$
79056
Prove that $\mathbb Z^n$ is not isomorphic to $\mathbb Z^m$ for $m\neq n$
137011
showing $\psi: R\to \mathbb C$ is ring isomorphism.
59995
Isomorphism between $\mathbb{C}^* $ under multiplication with $\mathbb{C}$ under addition.
84114
Does there exist a surjective homomorphism from $(\mathbb R,+)$ to $(\mathbb Q,+)$ ?
116168
Is $e^x$ the only isomorphism between the groups $(\mathbb{R},+)$ and $(\mathbb{R}_{> 0},*)$?
106178
Question of an isomorphism of $\epsilon_ 0$ and a subset of the rationals.
64025
Ring homomorphisms from $\Bbb Q$ into a ring
64419
How to construct a homomorphism from an abelian group to $\mathbb{Q}/\mathbb{Z}$?
89415
Number of homomorphisms from $(\mathbb Q^+ , \,\cdot\,)$ to $(\mathbb Z_n , +)$
129239
Additive quotient group $\mathbb{Q}/\mathbb{Z}$ is isomorphic to the multiplicative group of roots of unity
151993
Ring homomorphisms $\mathbb Z[x]\rightarrow \mathbb Q$