Two normal subgroups and isomorphism theorem
98765
Showing that $G/(H\cap K)\cong (G/H)\times (G/K)$
90449
Showing that a Sylow subgroup of a group of order $p^{2}q$ is normal.
136083
Show that $\sigma\circ\phi : G_1 \to G_3$ is an isomorphism
89508
Existence of normal subgroups for a group of order $36$
103002
Group equals union of two subgroups
1220
Have $\alpha:G \to H$. If a subgroup $U$ is normal in $H$ prove the pre-image of $U$ is normal in $G$.
128443
Isomorphism between finite groups
123860
When are two direct products of groups isomorphic?
44934
Show that every normal subgroup can be written as an intersection of $\ker \chi$'s for $\chi \in \operatorname{Irr}(G).$
25832
Let $K$ be a normal subgroup of order 2 in group $G$, show that $K$ lies in the centre of $G$
23941
Normal Subgroups that Intersect Trivially
67199
Isomorphism $H_n(D^n, S^{n - 1};A)$ and $A$
142413
Normal Subgroups of $SU(n)$
86336
For $G$ group and $H$ subgroup of finite index, prove that $N \subset H$ normal subgroup of $G$ of finite index exists
36709
subgroup of direct product of two groups
113357
Groups of order $pqr$ and their normal subgroups
15630
Normal subgroup of prime order is characteristic