Sorry for my bad English.
Let $G$ be a topological group, then we say $G$ is profinite if $G$ satisfies next equivalent condition as follow;
(i) $G$ is compact, Hausdorff, totally disconnected.
(ii)$G$ is compact, Hausdorff, unit element $1\in G$ has neighbourhood system consisted of normal subgroup.
But I can't understand why there are equivalent. Please tell me this proof or reference or hint, thanks.