Proving that $H=\{A\in GL(2,R)\mid AA^T=I\}$ is a subgroup of $GL(2,R)$
30877
How to show that the set of orthogonal n x n matrices forms a group under multiplication
98542
Prove that $H$ is a subgroup of an abelian group $G$
28108
Proving the kernel is a normal subgroup.
106779
How to show if $H,K$ are normal subgroups in a group $G$ then $[H,K] \leq H \cap K$
154398
Show that H is a subgroup of G
36137
Prove $GL_2(\mathbb{Z}/2\mathbb{Z})$ is isomorphic to $S_3$
144582
Index of a subgroup in $SL_2(\mathbb{Z})$
22477
If H is a subgroup of a group G and K is a normal subgroup of G the show that K is a normal subgroup of HK.
27056
$ gl(2,\mathbb C) \cong sl(2,\mathbb C) \oplus \mathbb C $
132342
Suppose $H$ is a subgroup of $S_n$ but $H$ is not a subgroup of $A_n$. Prove that |$H$ ∩ $A_n$| = $\frac{1}{2}|H|$?
29445
Trying to prove that $H=\langle a,b:a^{3}=b^{3}=(ab)^{3}=1\rangle$ is a group of infinite order.
28722
Prove that $H$ is a abelian subgroup of odd order
1220
Have $\alpha:G \to H$. If a subgroup $U$ is normal in $H$ prove the pre-image of $U$ is normal in $G$.
41237
$H$ is normal subgroup of $G$ iff $gHg^{-1}=H$ for every $g$ of $G$
146028
$GL(n, \mathbb{C})$ is isomorphic to a subgroup of $GL(2n, \mathbb{R})$
92033
Prove that $g$ is a submanifold: $g (t,u,v) = (t^2,u^2,v^2,\sqrt{2}uv, \sqrt{2}tv,\sqrt{2}tu)$
11000
Fundamental group of $\mathbb{R}^2 \setminus (\mathbb{Z} \times \{0\})$