$su(2) $ and $ sl(2;R)$ are not isomorphic?
68014
Prove that $\mathfrak{su}(2)$ is not isomorphic to $\mathfrak{sl}(2,\mathbb R)$
145462
On the canonical isomorphism between $V$ and $V^{**}$
86015
$\mathbb Q[x]/(x^2+1)$ is not isomorphic to $\mathbb Q[x]/(x^2+2)$
88474
$\mathbb{A}^{2}$ not isomorphic to affine space minus the origin
145700
Module isomorphic to second dual
142352
how to prove $G_1$ and $G_2$ aren't isomorphic?
72548
Lie group embeddings $SO(10) \supset SU(3) \times SU(2) \times U(1)?$
147827
How to calculate $|\operatorname {SL}_2(\mathbb Z/N\mathbb Z)|$?
94747
Show that the rings $2\mathbb{Z}$ and $3\mathbb{Z}$ are not isomorphic.
67374
Is it true that $\mathbb{R}$ and $\mathbb{R}^2$ are isomorphic as abelian groups?
121449
An isomorphism from $GL_{2}(\mathbb{F_{2}})$ to $S_{3}$
142413
Normal Subgroups of $SU(n)$
58135
Quotient group $SL(2,\mathbb{R})/SO(2,\mathbb{R})$
25050
To prove that $(F,+)$ and $(F-\{0\},\cdot)$ are not isomorphic as groups.
74675
Why is there no natural isomorphism between $V$ and its dual?
128603
Lie algebra and tangent space at the identity are isomorphic
156679
$K[X,Y]/(XY-1)$ not isomorphic to $K[T]$