quality:corruption
Example

This group is not abelian. For example, h j (a) = h (e 2 i π / 5 a) = e 4 i π / 5 a {\displaystyle hj(a)=h(e^{2i\pi /5}a)=e^{4i\pi /5}a}, whilst j h (a) = j (a) = e 2 i π / 5 a {\displaystyle jh(a)=j(a)=e^{2i\pi /5}a}, and in fact, j h = h j 3 {\displaystyle jh=hj^{3}}.