Not a normal subgroup by left and right coset
102622
K is a subgroup of G. Show that K is not a normal subgroup
16804
Prove whether or not a subgroup is normal in the dihedral group $D_4$
149416
Show that $ \{\lnot,\leftrightarrow\} $ is not functional complete
87534
Finitely generated group which is not finitely presented
18182
An abelian group $G$ with ${\rm Aut}(G)$ non-abelian
122266
equivalent definition of normal subgroup
116737
An element of a group $G$ is not conjugate to its inverse if $\lvert G\rvert$ is odd
75568
Subgroup of index $2$ is Normal
117479
Mutual set of representatives for left and right cosets: what about infinite groups?
97928
Normal subgroup of a normal subgroup
77297
Counterexample for $A,B\triangleleft G,G/A\cong B \Rightarrow G/B\cong A$
78580
Is $SL_n(\mathbb{R})$ a normal subgroup in $GL_n(\mathbb{R})$?
109072
Find the left cosets of subroups of $S_3$
86872
normalized subgroup by another subgroup
150207
Non isomorphic subgroups of cyclic groups
151559
Please help: How to show that Aut(G) is a subgroup of Sym(G)
135241
Show that $\mathbb{Z}/n^2\mathbb{Z}$ is not isomorphic to other group