proving that a group is a subfield of ℝ
46565
Show that $\mathbb{Q}(\sqrt{2})$ is a field.
145726
For a subfield $K$ of $\Bbb C$ with $K\nsubseteq \Bbb R$, show $K$ is dense in $\Bbb C$.
34700
Proving that the matrix exponential map is surjective onto the general linear group
68971
Elementary approach to proving that a group of order 9 is Abelian
58135
Quotient group $SL(2,\mathbb{R})/SO(2,\mathbb{R})$
50172
Show that $\mathbb{Q}(\sqrt{2})$ is the smallest subfield of $\mathbb{C}$ that contains $\sqrt{2}$
28108
Proving the kernel is a normal subgroup.
136770
Any field that contains the integers contains the rationals as a subfield (Analysis proof)
155125
Every ordered field has a subfield isomorphic to $\mathbb Q$?
11003
Proving that $G/N$ is an abelian group
64582
Group covered by finitely many cosets
8623
Finite subgroups of the multiplicative group of a field are cyclic
154398
Show that H is a subgroup of G
70394
Prove that $a * b$ is a group (Hungerford, 2nd ed., sec $7.2$, Exercise $22$)
29717
Not sure how to go about this group theory proof
68955
Characterising subgroups of Prüfer $p$-groups.
97637
Showing that isotropy groups are submanifolds