How to show that $\mathbb Q(\sqrt 2)$ and $\mathbb Q(\sqrt 5)$ are non-isomorphic?
38549
$\mathbb{Q}(\sqrt{n}) \cong \mathbb{Q}(\sqrt{m})$ iff $n=m$
66708
Elementary isomorphism between $\operatorname{PSL}(2,5)$ and $A_5$
61084
Examples of non-isomorphic fields with isomorphic group of units and additive group structure
93169
Show that $(\mathbb Z[x],+)$ and $(\mathbb Q_{>0},\cdot)$ are isomorphic groups
122083
Prove that $\sqrt[3]{2} +\sqrt{5}$ is algebraic over $\mathbb Q$
98731
Show that there is no epimorphism from ($\mathbb{Q}$, +) to ($\mathbb{Z}$, +)
149973
Showing the following coordinate rings are not isomorphic
129521
Is $\sqrt[3]{5}$ in $\mathbb Q(\sqrt[3]{2})$?
42810
Is $(\mathbb{Q},+)$ isomorphic to $(\mathbb{Q}^n,+)$?
98587
$\mathbb Z [X] / (X)$ isomorphic to $\mathbb Z[X] / (X+1)$ isomorphic to $\mathbb Z [X] / (X+2015)$
109596
Isomorphism from $\mathrm{Aut}(\mathbb{Z}/2\mathbb{Z}\times \mathbb{Z}/2\mathbb{Z})$ to $S_3$
18160
How to show that the group of nonzero real numbers under multiplication is not isomorphic to the group of real numbers under addition?
137285
Prove $\mathbb{Z}_2 \times \mathbb{Z}_2$ is not isomorphic to $\mathbb{Z}_4$
143831
Showing $\mathbb{Q}$ is homeomorphic to $\mathbb{Q}^2$
86015
$\mathbb Q[x]/(x^2+1)$ is not isomorphic to $\mathbb Q[x]/(x^2+2)$
83001
Easier way to show $(\mathbb{Z}/(n))[x]$ and $\mathbb{Z}[x] / (n)$ are isomorphic
89415
Number of homomorphisms from $(\mathbb Q^+ , \,\cdot\,)$ to $(\mathbb Z_n , +)$