$PSL(2, 11)$ has non isomorphic Hall subgroups
14895
Reference for the subgroup structure of $\rm{PSL}_2(q)$
122353
Status of the classification of non-finitely generated abelian groups.
83919
How to show $D_3\oplus D_4$ is not isomorphic to $D_{24}$?
88474
$\mathbb{A}^{2}$ not isomorphic to affine space minus the origin
150188
Construct a non-abelian group of order 75
71035
Non abelian subgroup of a abelian group.
75068
subgroups of $\mathbb Z / 2 \mathbb Z \times \mathbb Z / 2 \mathbb Z$
41688
An elementary problem in Group Theory: the unique noncyclic group of order 4
81238
Is $O(2)$ really not isomorphic to $SO(2)\times \{-1,1\}$?
9612
Frattini subgroup $Φ ( G )$ is not trivial
26749
$\mathbb{Z}[X]/(X^2-1)$ is not isomorphic with $\mathbb{Z}\times \mathbb{Z}$
113413
How do I show that two groups are not isomorphic?
27472
Prove that $PSL(2,\mathbb{Z})$ is free product of $C_2$ and $C_3$
157853
$Q_8$ is isomorphic to a subgroup of $S_8$, but not isomorphic to a subgroup of $S_n$ for $n\leq 7$.
141265
Finding a normal and not normal subgroup of $S_3$
128300
Prove that a group with exactly two proper nontrivial subgroups is isomorphic to $\mathbb{Z}_{pq}$ or $\mathbb{Z}_{p^3}$.
76732
Number of non-isomorphic groups of order 21