Solution
= Solution
For a <powerful pro-p group>, $\Phi(P_i)=P_{i+1}$. The <Burnside basis theorem> therefore gives
$$
d(P_i)=\dim_{\mathbb F_p}P_i/P_{i+1}=\log_p[P_i:P_{i+1}].
$$
If $G$ is uniform, all these indices equal $[G:P_2]=p^{d(G)}$. Hence \b[$d(P_i)=d(G)$ for every $i\ge1$], proving (i)$\Rightarrow$(ii).