Is this subset of group, a subgroup of it?
2761
If $S$ is a nonempty subset of group $G$, then $S^{|G|}$ is a subgroup of $G$.
80381
Groups with "few" subgroups
151559
Please help: How to show that Aut(G) is a subgroup of Sym(G)
3756
If $G$ is abelian, then the set of all $g \in G$ such that $g = g^{-1}$ is a subgroup of $G$
14301
Union of subgroups is a subgroup if and only if one subgroup is a subset of the other
149578
Subgroups of $(\mathbb Z_n,+)$
51352
Subgroups of a finite abelian group
151130
When is the product of $n$ subgroups a subgroup?
112407
Set of left cosets is a group
122821
Is the following proof valid? About the closure of a subgroup, of a topological group, being again a subgroup
120495
Does this correctly interpret the "$\cong$" between groups as "$=$" between sets?
43832
Which groups are derived subgroups?
124709
Suppose G be a non-abelian group and H,K be two abelian subgroups of G. Then must HK be an abelian subgroup of G?
133770
Subgroups of finite abelian groups.
124237
Group equals union of three subgroups
75068
subgroups of $\mathbb Z / 2 \mathbb Z \times \mathbb Z / 2 \mathbb Z$
12667
How many subgroups of order $n$ does $D_n$ have?