Concept of a normal subgroup
49257
How to show that Klein four-group is a normal subgroup of the alternating group $A_4$
7973
Groups of order $pq$ have a proper normal subgroup
19720
A normal subgroup intersects the center of the $p$-group nontrivially
55350
H is a subgroup of G and G' is a subgroup of H. Prove H is normal in G.
94999
A subgroup with an index of 2 is normal to the group.
111375
Normality of subgroups and Sylow groups under homomorphisms...
23941
Normal Subgroups that Intersect Trivially
49122
Why commutator subgroup is normal to G?
103423
Normal subgroup where G has order prime
75590
How many normal subgroups does a non-abelian group $G$ of order $ 21$
152904
Groups with Same Number Of Elements and Subgroups
1360
Every group of order $150$ has a normal subgroup of order $25$
101079
Inner automorphisms form a normal subgroup of $\operatorname{Aut}(G)$
55493
Showing that the path-connected component of the identity matrix in a subgroup of $GL_n(\Bbb R)$ is a normal subgroup
141043
$H$ normal in $G$. Need $G$ contain a subgroup isomorphic to $G/H$
54911
The preimage of a normal subgroup under a group homomorphism is normal
59561
Suppose that G is a group and N < G a normal subgroup. Prove G/N is simple