Show that F2 has an infinite index free subgroup of rank 2
98474
Show the existence of a certain subgroup of F2
14895
Reference for the subgroup structure of $\rm{PSL}_2(q)$
61064
Finite index subgroup $G$ of $\mathbb{Z}_p$ is open.
113936
Showing that a finite abelian group has a subgroup of order m for each divisor m of n
154398
Show that H is a subgroup of G
75568
Subgroup of index $2$ is Normal
91874
Existence of finite indexed normal subgroup for a given finite indexed subgroup.
12455
$|G|>2$ implies $G$ has non trivial automorphism
64193
Cardinality of Infinite Symmetric group
139451
Prove that any two nontrivial subgroups of $\mathbb{Q}$ have nontrivial intersection
76962
Sylow $p$-subgroups of $GL_n(\mathbb{F}_p)$
9232
Group with proper subgroups infinite cyclic
88718
A group is generated by two elements of order $2$ is infinite and non-abelian
158142
Total space of a finite rank locally free sheaf, Vakil's 17.1.4 & 17.1.G
90525
The subspace of $\ell_2$
110708
On proving that a finitely generated group has a finite number of subgroups with index $n$.
9612
Frattini subgroup $Φ ( G )$ is not trivial