Akka docs, 2.3.1: "Akka implements a specific form called “parental supervision”. Actors can only be created by other actors—where the top-level actor is provided by the library—and each created actor is supervised by its parent. This restriction makes the formation of actor supervision hierarchies explicit ..."

Shouldn't the last word be implicit, because by creating a child actor the actor becomes a supervisor automatically, i.e. implicitly.