Fig. 10From: Two metrics on rooted unordered trees with labelsA 1-level tree \(T_{13}\) (upper left), its level-2 completion \({\bar{T}}_{13}(2)\) (upper right) and its level-3 completion \({\bar{T}}_{13}(3)\) (lower). The level (Lv.) of each vertex is marked on the leftBack to article page