 When the iTree is fully grown, each point in X is isolated at one of the external nodes.Intuitively, the anomalous points are those (easier to isolate, hence) with the smaller "path length" in the tree, where the path length h(xi) of point formula_1 is defined as the number of edges xi traverses from the root node to get to an external node.A probabilistic explanation of iTree is provided in the iForest original paper.