Prove that a certain element of the commutator subgroup of $F_4$ is not a commutator
128428
Why is the set of commutators not a subgroup?
68014
Prove that $\mathfrak{su}(2)$ is not isomorphic to $\mathfrak{sl}(2,\mathbb R)$
88645
Prove that the additive groups $\mathbb{R}$ and $\mathbb{Q}$ are not isomorphic.
80186
How to show that $K\leq S_4$ is a normal subgroup?
134686
$D_3\oplus D_4$ not isomorphic to $D_{24}$
80273
Prove the centralizer of an element in group $G$ is a subgroup of $G$
37904
Prove that the multiplicative groups $\mathbb{R} - \{0\}$ and $\mathbb{C} - \{0\}$ are not isomorphic.
68672
Commutator subgroup of rank-2 free group is not finitely generated.
95867
Subgroup of $C^*$ (nonzero complex) with finite index.
3296
Proof That $\mathbb{R} \setminus \mathbb{Q}$ Is Not an $F_{\sigma}$ Set
126771
Group element not taken to its inverse by any automorphism
61373
A normal subgroup that is not a characteristic
145159
Finite group is abelian if the representatives of its conjugacy classes commute
144988
Commutator Subgroup of Direct Product equals the Direct Product of the Commutator Subgroups
87682
Show that $\sqrt{2}\notin \mathbb{Q}(\sqrt[4]{3})$
90511
Commutator subgroup of a dihedral group.
42891
Prove that $Z(G)$ which is the center of $G$ is a subgroup of $G$