Say G a p-group, M normal abelian subgroup of G such that $\frac{G}{M} \cong C_{p^{n}}.$ It exists $g \in G - M $ such that $G=M<g>.$ I showed that the derived subgroup is $G' = [M,g].$ 1) Is it true that $C_{G}(G')=MZ(G) ?$ 2) When is this assertion true? 3) In a metabelian p-group G' is abelian, so it's contained in its centralizer, right? When is it self centralizing? Best regards Marco, PhD student.