# Changes

* [[Commutator subgroup centralizes cyclic normal subgroup]]: In particular, the cyclic part in a dihedral group is contained in the [[centralizer of commutator subgroup]] for all $n$. The cases $n = 2,4$ need to be excluded because these are the only cases where the centralizer of commutator subgroup is ''bigger'', i.e., the whole group.
===Odd versus even $n$===