Tower law for subgroups
74970
Subsubgroups are subgroups of subgroups / Multiplicative Property of the Index
96614
Finite number of subgroups $\Rightarrow$  finite group
137691
What are the self-normalizing subgroups of $S_n$?
99346
Prove a result on transitive group actions.
45028
How to show that $\langle a \rangle$ is a subgroup of a group $G$, where $a$ is in center of the group $G$
33868
A transformation between two free group actions.
30793
Intuition behind normal subgroups
146760
Prove that H is a subgroup of G
68422
Understanding Lagrange's Theorem (Group Theory)
61226
Group Structure on $\Bbb R$
102912
Subgroups of finitely generated groups are not necessarily finitely generated
98474
Show the existence of a certain subgroup of F2
133770
Subgroups of finite abelian groups.
144788
Cosets of a subgroup do not overlap
114811
Characteristic subgroups and automorphisms
36709
subgroup of direct product of two groups
111375
Normality of subgroups and Sylow groups under homomorphisms...