What about the index of this subgroup?
92050
Poincaré's theorem about groups
40908
Raised index of partial derivative
155502
Index of a maximal subgroup in a finite group
115849
Are the Groups having all subgroups of same order conjugate classified?
98474
Show the existence of a certain subgroup of F2
54082
Group with exactly two subgroups of index 2
7530
Why this $\sigma \pi \sigma^{-1}$ keeps appearing in my group theory book? (cycle decomposition)
123560
Intuition behind why order of a subgroup divides order of a group.
57309
Show that the free group on $n$ generators is a finite index subgroup of $F_2$
39938
Subgroups of a cyclic group and their order.
108049
Determining the number of subgroups of $\Bbb Z_{14} \oplus \Bbb Z_{6}$
86336
For $G$ group and $H$ subgroup of finite index, prove that $N \subset H$ normal subgroup of $G$ of finite index exists
155054
$G$ be a group and $H$ be a normal subgroup of index $p$ ( a prime ) ; suppose $K$ is a subgroup of $G$ not contained in $H$ , then $G=HK$?
151210
How can we find and categorize the subgroups of $\mathbb{R}$?
88344
Order of a group and subsequent subgroups
53409
Show group of order $4n + 2$ has a subgroup of index 2.
62255
Notation question: Subroup generated by two elements?