Show that there are only two types of subgroups in R , either Discrete or Dense?
33309
Subgroup of $\mathbb{R}$ either dense or has a least positive element?
113925
Normal Subgroup Counterexample
34067
Is there a general formula for finding all subgroups of dihedral groups?
110957
No non-trivial clopen sets in $\mathbb{R}$? How to give a direct proof?
5996
Are $(\mathbb{R},+)$ and $(\mathbb{C},+)$ isomorphic as additive groups?
74498
Smallest dense subset of $\mathbb{R}$
63253
Computing easy direct limit of groups
103829
Find the subgroups of A4
80381
Groups with "few" subgroups
15396
Enumerating all subgroups of the symmetric group
27780
Subgroup which is generated by odd elements
54082
Group with exactly two subgroups of index 2
23941
Normal Subgroups that Intersect Trivially
151862
Is any subgroup of a direct product isomorphic to a direct product of subgroups?
104112
Number of finite simple groups of given order is at most $2$ - is a classification-free proof possible?
58076
Subgroup generated by a set
157330
Showing the image of a subgroup is a subgroup.